Manchester 8360 Manual

Green Mountain Insert 70 (Model 8450)

Manual: 6400-41414

R: 08/05/19

Green Mountain Insert 70

(Model 8450)

Wood Fireplace Insert

OWNER'S MANUAL

Installation And

Operating Instructions

SAVE THIS OWNER’S MANUAL FOR FUTURE REFERENCE

PLEASE READ THIS ENTIRE OWNER’S MANUAL BEFORE YOU INSTALL AND USE YOUR

NEW GREEN MOUNTAIN INSERT 70 WOOD FIRPLACE INSERT.

If this room heater is not properly installed, a house fire may result.

To reduce the risk of fire, follow the installation instructions.

Failure to follow these instructions can result in property damage, bodily injury, or even death.

Conforms to UL Std. 1482 & 737

Certified to ULC Std. S628

CONTACT LOCAL AUTHORITIES WITH

JURISDICTION (BUILDING

DEPARTMENT or FIRE OFFICIALS),

ABOUT PERMITS REQUIRED,

RESTRICTIONS AND INSTALLATION

INSPECTION IN YOUR AREA.

Safety tested according to ULC S628,

UL 737 and UL 1482 Standards

by an accredited laboratory

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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NOTES ON INSERT OPERATION AND EFFICIENCY

Rating:

You have purchased a HearthStone Green Mountain Insert 70 tested to CFR 40 part 60, subpart AAA, section 60.534(a)(1(ii)

and draft ASTM WK47329-14 where applicable. This insert is certified to comply with the U.S. Environmental Protection

Agency 2020 particulate emissions standard using cord wood. It is certified at 1.54 gr/hr. emission rate and under specific

test conditions has been shown to deliver heat at rates ranging from 14,800 to 28,600 Btu (output).

This wood heater has a manufacturer-set minimum allowable low burn rate that must not be altered. It is against federal

regulations to alter this setting or otherwise operate this wood heater in a manner inconsistent with operating instructions in

this manual.

Please refer to the Warranty section of this manual for registration instructions. In case of warranty claims, please contact

the point of original sale or the nearest authorized HearthStone dealer. Our dealer network processes all warranty claims.

Authorized HearthStone dealers can be located at www.hearthstonestoves.com.

This heater is designed to burn natural wood only. Higher efficiencies and lower emissions generally result when burning

air-dried seasoned hardwoods, as compared to softwoods or to green or freshly cut hardwoods. DO NOT BURN: Garbage,

lawn clippings, material containing rubber (including tires), materials containing plastic, waste petroleum products paints or

paint thinners, asphalt products, materials containing asbestos, construction or demolition debris, railroad ties, pressure

treated wood, manure or animal remains, salt water driftwood or other previously salt water saturated materials, unseasoned

wood, paper products, cardboard, plywood or particleboard. This prohibition against burning these materials does not

prohibit the use of fire starters made from paper, cardboard, sawdust, wax and similar substances for the purpose of starting

a fire in an affected wood heater. Burning these materials may result in a release toxic fumes or render the heater ineffective

and cause smoke.

Following the maintenance guidelines set forth in this manual will help insure the efficient use of your wood heater and

minimize visible emissions. Having your insert inspected by a trained professional on a regular basis will greatly increase

the potential for recognizing potential impacts to efficiency.

Proper draft is important to the efficient operation of your heater. Refer to the Normal Operation section of this manual for

information regarding adequate draft. Both excessive and sub-minimum draft can affect the efficiency of your wood heater.

Excessive draft can lead to over-consumption of fuel, lower overall heating capacity of the fireplace insert and potential over

firing. Low draft can result in inefficient burns, low heat output, expulsion of smoke into the living area when fireplace insert

doors are opened and an increased potential for build-up of flammable materials in the flue.

Efficiency:

Efficiency was measured and weighted using CFR 40 part 60, subpart AAA, section 60.534(a)(1(ii) and draft ASTM

WK47329-14 and CSA B415.1-10 methodology. A weighted average was used to calculate the overall efficiency across all

of the 4 burn rate categories using the higher heating value (HHV). The weighted average efficiency is 69% (HHV).

To maximize the efficiency of your wood fireplace insert make sure it is sized properly for the space you plan to heat. An

oversized fireplace insert will often be forced to burn at a lower and dirtier burn rate. Consult with your dealer for sizing and

correctly placing the fireplace insert in your home. An incorrectly placed fireplace insert can greatly reduce efficiency.

Maximizing the efficiency of your fireplace insert will heat your house quickly, burn cleaner and use less wood.

Refer to the Choosing Firewood section of this manual for appropriate fuel selection. Seasoned firewood is typically at or

near 20% moisture content. This can be measured with any number of hand-held moisture meters available through your

local hearth shop. Follow instructions included in the meter you purchase to measure fuel wood moisture content. Burn only

dry, seasoned wood as using wet wood will greatly reduce your efficiency.

CO Emissions:

The Green Mountain Insert 70 has an average CO emission rate over all burn categories of 89.4 g/hr. Wet wood or

unapproved fuel described above can greatly affect the emissions of a wood burning fireplace insert.

Smoke/Fire/CO Detectors:

It is highly recommended that smoke and CO detectors be installed throughout the heated space when a wood burning

heater is installed. Be certain to install these devices not only in the area where the wood appliance is located, but also in

bedrooms, hallways leading to other areas of the house and all common areas of the heated space. Check the batteries in

these devices and assure operation by performing whatever test operations are recommended by the manufacturer.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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Table of Contents

INTRODUCTION ..................................................................................................................... 4

CODES AND SAFETY INFORMATION .......................................................................................................................... 4

PERIODIC CHECKLIST AND EMERGENCY PROCEDURES ............................................................................................. 6

SPECIFICATIONS .................................................................................................................. 7

INSTALLATION ...................................................................................................................... 8

UNPACKING ............................................................................................................................................................ 8

ZONE HEATING ....................................................................................................................................................... 8

MASONRY FIREPLACE REQUIREMENTS .................................................................................................................... 8

CERTIFICATION LABEL ............................................................................................................................................ 9

MASONRY FIREPLACE THROAT DAMPER .................................................................................................................. 9

INSTALLATION OF A COMBUSTIBLE MANTEL SHELF ................................................................................................. 10

HEARTH REQUIREMENTS & FLOOR PROTECTION.................................................................................................... 10

MINIMUM MASONRY OPENING ............................................................................................................................... 13

COMBUSTIBLE SURFACE REQUIRED CLEARANCES ................................................................................................. 13

INSTALLING THE INSERT ........................................................................................................................................ 14

OUTSIDE AIR SUPPLY ........................................................................................................................................... 16

THE VENTING SYSTEM ....................................................................................................... 18

GENERAL INFORMATION ........................................................................................................................................ 18

CHIMNEY AND LINER INFORMATION ........................................................................................................................ 18

LINER CONNECTION .............................................................................................................................................. 19

MINIMUM CHIMNEY CLEARANCES .......................................................................................................................... 20

CHIMNEY LOCATION ............................................................................................................................................. 21

SUPPLY OF COMBUSTION AIR................................................................................................................................ 22

OPERATION ......................................................................................................................... 23

CONTROLS AND FEATURES ................................................................................................................................... 23

BLOWER OPERATION ............................................................................................................................................ 23

CHOOSING FIREWOOD .......................................................................................................................................... 24

BUILDING A FIRE .................................................................................................................................................. 25

BREAKING IN YOUR WOOD FIREPLACE INSERT ....................................................................................................... 25

NORMAL OPERATION ............................................................................................................................................ 26

OVER-FIRE CAUTION ............................................................................................................................................ 27

FIRE SCREEN ....................................................................................................................................................... 28

MAINTENANCE .................................................................................................................... 29

CREOSOTE FORMATION & REMOVAL AND GENERAL MAINTENANCE .......................................................................... 29

GLASS AND BLOWER REPLACEMENT PROCEDURES ................................................................................................ 30

DOOR ADJUSTMENT ............................................................................................................................................. 32

REFRACTORY, SECONDARY AIR TUBES AND BAFFLE ................................................................................................ 32

REMOVAL INSTRUCTIONS ...................................................................................................................................... 33

ILLUSTRATED PARTS LIST ................................................................................................ 34

REPLACEMENT KITS & OPTIONAL ACCESSORIES .................................................................................................... 37

TROUBLESHOOTING .......................................................................................................... 38

SAFETY LABEL ................................................................................................................... 40

LIMITED WARRANTY .......................................................................................................... 41

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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INTRODUCTION

Thank you for purchasing a Green Mountain Insert

70 wood fireplace insert from HearthStone Quality

Home Heating Products. This fireplace insert will

provide years of comfortable heat. This fireplace

insert combines the warmth and comfort of

soapstone and cast iron with the efficiency of

advanced combustion technology. The Green

Mountain Insert 70’s large glass window allows you

to enjoy the fire from a variety of locations in the

room. We trust that you will appreciate the quality of

this product.

Your Green Mountain Insert 70 wood fireplace insert

burns very efficiently and produces a large amount

of heat. However, you should not consider your

Green Mountain Insert 70 the sole heat source for

your home.

Please read this manual in its entirety. Its purpose is

to familiarize you with your fireplace insert's safe

installation, proper break-in, operation and

maintenance. It contains extremely important

information so keep it handy and refer to it often.

A qualified heating technician may need this owner’s

manual as a reference when installing this fireplace

insert in your home. There are national, state, and

local building codes that direct the technician on how

to install your fireplace insert. These codes stipulate

the dimension of stovepipe and clearances to walls,

ceilings, hearth, and other combustible surfaces.

The codes exist to reduce the risk of fire. Failure to

follow these instructions can result in fire, property

damage, bodily injury, and even death.

It is extremely important to install this fireplace insert

with the proper clearance from combustible

surfaces. You can purchase specific connector pipe

and special wall coverings as specified by this

manual and the NFPA 211 code to protect

combustible surfaces. As a general rule, keep

furniture, drapes, curtains, wood, paper, and other

combustibles at least 36 inches (92 cm) away from

the fireplace insert. Never install the fireplace insert

in or near a storage location for gasoline, kerosene,

charcoal lighter fluid or any other flammable liquids.

Install the fireplace insert in your central living area

to allow heat to radiate naturally to distant rooms. Do

not install your fireplace insert in a poorly insulated

area. This is inefficient and would likely result in

higher fuel usage.

 SAFETY NOTICE:

AN IMPROPERLY INSTALLED FIREPLACE INSERT

CAN RESULT IN A HOUSE FIRE. FOR YOUR

SAFETY, CAREFULLY FOLLOW THE

INSTALLATION DIRECTIONS. CONTACT LOCAL

BUILDING OR FIRE OFFICIALS ABOUT

RESTRICTIONS AND INSTALLATION INSPECTION

IN YOUR AREA.

The safety of your fireplace insert will depend on

many factors, some of which include: distance to

combustible objects, correct venting, and adequate

chimney maintenance. Should you have any

questions, do not hesitate to contact your dealer for

additional information.

Contact your dealer for any necessary warranty

service.

This Green Mountain Insert 70 Model 8450 fireplace

insert is warranted by:

HearthStone Quality Home Heating Products, Inc®

317 Stafford Ave.

Morrisville, Vermont 05661, USA

www.hearthstonestoves.com

CODES

When you install your Green Mountain Insert 70

wood fireplace insert, it is imperative that you adhere

to all Federal and local codes. Obtain these codes

from either of the following sources:

American National Standards Institute, Inc. (ANSI)

1430 Broadway

New York, NY 10018

www.ansi.org

National Fire Protection Association, Inc. (NFPA)

Battery March Park

Quincy, MA 02269

www.nfpa.org

SAFETY INFORMATION

Read and understand this Owner's Manual

thoroughly before installing and using this

fireplace insert.

Make sure to install your fireplace insert:

 According to the manufacturer's

recommendations

 In accordance with all applicable codes

 With the proper sized chimney

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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 When installed and operated as described in

these instructions, the Green Mountain Insert 70

wood insert is suitable for use in residential

installations. The Green Mountain Insert 70

wood insert is not intended for installation in a

bedroom.

 The information given on the certification label

affixed to the appliance always overrides the

information published, in any other media

(owner’s manual, catalogues, flyers, magazines

and web sites).

 Mixing of appliance components from different

sources or modifying components may result in

hazardous conditions. Where any such changes

are planned, HearthStone should be contacted

in advance.

 Any modification of the appliance that has not

been approved in writing by the testing authority

violates CSA B365 (Canada), and ANSI NFPA

211 (USA).

 Connect this insert only to a listed stainless steel

chimney liner for use with solid fuel.

 If required, a supply of combustion air shall be

provided to the room.

 Do not connect to or use in conjunction with any

air distribution ductwork unless specifically

approved for such installation.

 Do not connect this unit to a chimney flue

serving another appliance.

 The insert and its stainless steel chimney liner

are to be installed only within a lined masonry

chimney and masonry fireplace conforming to

building codes for use with solid fuel. Do not

remove bricks or mortar from the existing

fireplace when installing the insert.

 In Canada, the CSA B365 Installation Code for

Solid Fuel Burning Appliances and Equipment

and the CSA C22.1 Canadian National Electrical

Code are to be followed in the absence of local

code requirements. In the USA, the ANSI NFPA

211 Standard for Chimneys, Fireplaces, Vents

and Solid Fuel-Burning Appliances and the ANSI

NFPA 70 National Electrical Code are to be

followed in the absence of local code

requirements.

 This insert must be installed with a continuous

chimney liner of 6" diameter extending from the

insert to the top of the chimney. The chimney

liner must conform to the Class 3 requirements

of CAN/ULC-S635, Standard for Lining Systems

for Existing Masonry or Factory-built Chimneys

and Vents, or CAN/ULC-S640, Standard for

Lining Systems for New Masonry Chimneys.

 The insert is not approved for use with a so-

called “positive flue connection” to the clay tile of

a masonry chimney.

When using your fireplace insert, follow these

safety precautions:

 Never burn kiln dried, painted or treated wood in

this fireplace insert.

 DO NOT BURN GARBAGE. Never burn

garbage or trash, colored or glossy paper,

solvents, plywood, artificial logs, cardboard, or

driftwood, in this fireplace insert.

 Never burn coal in this fireplace insert.

 DO NOT BURN FLAMMABLE FLUIDS.

 DO NOT USE CHEMICALS OR FLUIDS TO

START THE FIRE. Never use gasoline,

kerosene, charcoal lighter fluid, or other

flammable fluids to start or invigorate the fire.

These fuels will cause dangerous burning

conditions in the fireplace insert. Keep all such

materials away from the fireplace insert.

 Never use a wood grate or other device to

elevate the fire.

 Never allow logs in the firebox to hit the glass

when the door is closed.

 Never slam the door or use the door to force

wood in to the fireplace insert.

 Never over-fire your fireplace insert. (See page

27)

 Never put articles of clothing or candles on a hot

fireplace insert.

 Never connect the fireplace insert to a flue used

by another appliance.

Other safety guidelines:

 Keep all combustible items such as furniture,

drapes, clothing, and other items, at least 36"

(0.92 m) from the fireplace insert (See page

114)

 Install a smoke detector, preferably in an area

away from your wood fireplace insert.

 Keep a fire extinguisher handy. We recommend

the type rated "A B C."

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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 Dispose of ashes properly. (See page 29)

 Keep children and pets away from the fireplace

insert when it is burning; they could be seriously

injured by touching a hot fireplace insert.

 Clean your chimney system as needed. (See

page 29)

 Outside combustion air may be required if:

1. This solid-fuel-fired appliance does not

draw steadily, smoke rollout occurs, fuel

burns poorly, or back-drafts occur whether

or not there is combustion present.

2. Existing fuel-fired equipment in the house,

such as fireplaces or other heating

appliances, smell, do not operate properly,

suffer smoke roll-out when opened, or

back-draft whether or not there is

combustion present.

3. Opening a window slightly on a calm

(windless) day alleviates any of the above

symptoms.

4. The house is equipped with a well-sealed

vapor barrier and tight fitting windows

and/or has any powered devices that

exhaust house air.

5. There is excessive condensation on

windows in the winter.

6. A ventilation system is installed in the

house.

If these or other indications suggest that infiltration

air is inadequate, additional combustion air should

be provided from the outdoors. Outside combustion

air can be provided to the appliance by using the

optional outside air kit #94-53500

PERIODIC CHECKLIST

Perform each of these tasks at the specified

intervals.

At the End of Every Week:

 Empty ashes from the firebox, sooner if the

firebox is full.

At the Beginning of Every Other Month:

 Depending upon your use of the fireplace insert,

visually inspect the chimney connector and

chimney for creosote. (see page 29)

 Check door seals using the "dollar bill test." -

When the fireplace insert is cool, shut the door

on a dollar bill. If the bill pulls out without any

resistance, then your fireplace insert’s door is

not sealing properly. To tighten the seal, adjust

the door latch mechanism or change the door

gasket. (Refer to page 29.)

At the End of Every Season:

 Dismantle the chimney connector and clean it

thoroughly. Replace any pieces that show signs

of rust or deterioration.

 Inspect and, if necessary, clean your chimney.

 Clean out the inside of the fireplace insert

thoroughly.

 Inspect all door gasket material and replace if

worn, frayed, cracked or extremely hard.

EMERGENCY PROCEDURES

If you have a stovepipe or chimney fire, follow these

instructions:

1. If the fire is too threatening, leave the area and

call the fire department immediately! If not,

perform the next three steps.

2. Close the primary air control.

3. Close the stovepipe damper (if present).

4. Keep the fireplace insert front door closed!

 WARNING: DO NOT ATTEMPT TO PUT OUT A

STOVEPIPE OR CHIMNEY FIRE BY THROWING

WATER ONTO THE FIREPLACE INSERT,

STOVEPIPE, OR CHIMNEY. THE EXTREMELY

HIGH TEMPERATURE OF SUCH FIRES CAN

CAUSE INSTANTANEOUS STEAM AND SERIOUS

BODILY HARM.

Once the chimney fire expires, leave the primary air

control closed and let the fire in the fireplace insert

die out completely. Inspect the fireplace insert,

stovepipe, and chimney thoroughly for any sign of

damage before firing the fireplace insert again. You

must correct any damage before using your fireplace

insert again. We recommend having the fireplace

and the insert verified by a certified sweep or a fire

marshal before using the insert after a chimney fire.

Establish a routine for the fuel, wood burner and

firing technique. Check daily for creosote build-up

until experience shows how often you need to clean

to be safe. Be aware that the hotter the fire the less

creosote is deposited, and weekly cleaning may be

necessary in mild weather even though monthly

cleaning may be enough in the coldest months.

Contact your local municipal or provincial fire

authority for information on how to handle a chimney

fire. Have a clearly understood plan to handle a

chimney fire.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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Specifications

Maximum Heat Output:

28,600 BTUs per hour of cordwood (based on

independent laboratory test results).

Floor Size of Heated Area:

Up to a maximum of 2,000 square feet. Factors

unique to your home can reduce the square

footage the fireplace insert will heat. Home

insulation value, number and efficiency of

windows, floor plan, fireplace placement, quality

of the fuel and other conditions may limit the

heating ability of the fireplace insert.

Firebox Capacity:

2.4 cubic feet.

Maximum Log Length: Up To 20” (50.8 cm).

Emissions: 1.54 g/hr.

Burn Time: HeatLife Up to 8+ hrs. Note: The

amount and weight of wood contained per cubic

foot of firebox volume can vary from 10 to 25

lbs. per cubic foot depending on type of wood,

moisture content, packing density and other

factors.

Fireplace insert Dimensions:

Height: 25 3/4” (65.4cm)

Width: 33 1/2" (85.1cm)

Depth: 19 5/8" (49.8cm)

Weight: 513 lbs. (233 kg)

Connector Size: 6" (152 mm) diameter

Metal Chimney: 6" (152 mm) inside diameter

Masonry Chimney: 6” (152 mm) inside diameter

(round flue), 8” x 8” (203 x 203 mm) (square

flue)

Crate Dimensions: H-34” W-30” L-35” or

86.5x76.5x 89cm

Optional Equipment:

Outside Air Kit 94-53500

Steel Surround 94-5950110

Surround Lower Panel 94-5950510

Surround Extension 94-5950010

Fire Screen Insert 94-69500

Figure 1 – Green Mountain Insert 70 Dimensions

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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Installation

Read this chapter to obtain a sound understanding

of how to properly install your Fireplace Insert.

Contact the following agency for more information:

National Fire Protection Agency

Batterymarch Park

Quincy, MA 02269

1-800-344-3555

1-617-770-3000

www.nfpa.org

UNPACKING

HearthStone packages your Green Mountain Insert

70 wood fireplace insert with the greatest care so

that it ships safely. Under certain circumstances,

however, damage may occur during transit and

handling. When you receive the Green Mountain

Insert 70, carefully unpack and inspect the fireplace

insert and all accompanying parts. Ensure that all

parts are included inside the fireplace insert. If any

parts are damaged or missing, please contact your

authorized HearthStone dealer immediately.

Be sure to remove the packaging material in the

flue collar and above the baffle before installing the

chimney.

PACK LIST

1. Green Mountain Insert 70 Model 8450

Wood Fireplace Insert

2. Two boxes containing soapstone lining

3. Owner’s Manual

4. Leveling bolts (x2)

5. Spacers for soapstone (x2)

6. Metal label for fireplace installation

7. Brackets for chimney liner (x3)

ZONE HEATING

Your new Green Mountain Insert 70 wood insert is

a space heater, which means it is intended to heat

the area it is installed in, as well as spaces that

connect to that area, although to a lower

temperature. This is called zone heating and it is an

increasingly popular way to heat homes or spaces

within homes.

Zone heating can be used to supplement another

heating system by heating a particular space within

a home, such as a basement family room or an

addition that lacks another heat source.

Houses of moderate size and relatively new

construction can be heated with a properly sized

and located wood insert. Whole house zone heating

works best when the insert is located in the part of

the house where the family spends most of its time.

This is normally the main living area where the

kitchen, dining and living rooms are located. By

locating the insert in this area, you will get the

maximum benefit of the heat it produces and will

achieve the highest possible heating efficiency and

comfort.

The space where you spend most of your time will

be warmest, while bedrooms and basement (if there

is one) will stay cooler. In this way, you will burn

less wood than with other forms of heating.

Although the insert may be able to heat the main

living areas of your house to an adequate

temperature, we strongly recommend that you also

have a conventional oil, gas or electric heating

system to provide backup heating.

Your success with zone heating will depend on

several factors, including the correct sizing and

location of the insert, the size, layout and age of

your home and your climate zone. Three-season

vacation homes can usually be heated with smaller

inserts than houses that are heated all winter.

MASONRY FIREPLACE REQUIREMENTS

The masonry fireplace must meet the minimum

requirements found in the building code enforced

locally, or the equivalent for a safe installation.

Contact your local Building Inspector for

requirements in your area. An inspection of the

fireplace should include the following:

CONDITION OF THE FIREPLACE AND CHIMNEY:

 The masonry fireplace and chimney should be

inspected prior to installation, to determine that

they are free from cracks, loose mortar,

creosote deposits, blockage, or other signs of

deterioration. If evidence of deterioration is

noted, the fireplace or chimney should be

upgraded and/or cleaned prior to installation.

 Masonry or steel, including the damper plate,

may be removed from the smoke shelf and

adjacent damper frame if necessary to

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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accommodate the insert’s chimney liner,

provided that their removal will not weaken the

structure of the fireplace and chimney, and will

not reduce protection for combustible materials

to less than that required by the building code.

CHIMNEY CAPS:

 Mesh type chimney caps must have

provision for regular cleaning, or the mesh

should be removed to eliminate the

potential of plugging.

CLEARANCE TO COMBUSTIBLES:

 The fireplace should be inspected to make

sure that there is adequate clearance to

combustibles, both exposed combustibles

to the top, side, and front as well as

concealed combustibles, in the chimney

and mantle area. Your local inspector

should have information on whether older

fireplaces are of adequate construction.

OPENING SIZE:

 Refer to page 13 Minimum Masonry

Opening for suitable size fireplace

openings.

CERTIFICATION LABEL

The label is on a metal plaque in the blower space

below the firebox. It is attached with a lanyard to the

firebox so it can pull out far enough for inspection.

Take care when lifting and installing the insert to

keep the label inside the firebox to avoid any

damage.

Figure 2 - Label Location

Since the information given on the certification label

attached to the appliance always overrides the

information published in any other media, it is

important to refer to it to have a safe and compliant

installation. The model and the serial number can

also be found on the label.

It is recommended to note the insert serial number

on this manual. It will be needed to identify the

version of the appliance in the event replacement

parts or technical assistance is required. It is also

recommended to register the warranty online at

www.hearthstonestoves.com

MASONRY FIREPLACE THROAT DAMPER

If the fireplace's draft control system is to remain in

the masonry fireplace, it must be locked open for

access of the chimney liner or removed entirely. If

you remove draft control system from the masonry

hearth, you will need to install the metal plate

(27009), supplied with the owner’s manual kit,

indicating that the masonry hearth has been

modified. It must be secured inside the masonry

hearth, in a visible place and easy to locate.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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INSTALLATION OF A COMBUSTIBLE

MANTEL SHELF

It is possible to install a combustible shelf with a

maximum depth of 12" at a height of at least 27"

above the insert. At a height of more than 27", the

shelf must still have a maximum depth of 12".

Figure 3 – Mantel Shelf

HEARTH REQUIREMENTS & FLOOR

PROTECTION

Ensure you protect combustible flooring with a

covering of noncombustible material. The minimum

floor protection must be met under the fireplace

insert and extend beyond the fireplace insert as

follows:

FLOOR PROTECTION

Canada

USA

B

18" (457 mm)

1

16" (406 mm)

1

M

8" (203 mm)

N/A

N

N/A

8" (203 mm)

Figure 4 – Hearth Requirements

1

From door opening. The depth of the hearth extension in

front of the insert is included in the calculation of the floor

protector’s dimensions. The masonry hearth should be at

least 5" (127 mm) higher than the combustible floor in

front of it and a floor protection must extend at least 16"

(406 mm USA) and at least 18" (457 mm Canada) without

an R value. If the hearth elevation is lower than 5" (127

mm), the non-combustible floor protector in front of the

insert should have an R value equal or greater than 1.00

and shall extend 23" (584 mm) in front of the unit.

MAXIMUM MANTEL

SHELF DIMENSION (X)

MANTEL SHELF

CLEARANCES (I)

12" (305 mm) max.

27" (686 mm) min.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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To determine the need to add floor protection (D)

beyond the hearth extension, do the following

calculation using the data in following table: D = B -

(A - C).

The standard configuration of the insert leaves no

projection of the convection air jacket in front of the

fireplace opening. Therefore, the minimum

projection is 0''. Although it is possible to position

the insert to obtain a projection of 2'' (51 mm) or 4''

(102 mm) of the convection air jacket in front of the

fireplace opening with the use of the surround

extension. The choice of the configuration will

depend on the previous installation instructions and

compliance with building code.

If the value (D) is negative or zero, additional floor

protection in front of the unit is not needed because

the masonry fireplace hearth extension is large

enough. If the value (D) is positive, an additional

floor protection in front of the hearth extension at

least equivalent to the result (D) must be added.

Maximum

Extended

Minimum

Extended

A

Dimensions of

the hearth

extension

Dimensions of the

hearth extension

B

See the following

sections

See the following

sections

C

2" / 4"

(51 / 102 mm)

0"

(0 mm)

D

D=B-(A-C)

E

10" / 12"

(254 / 305 mm)

14"

(356 mm)

Air

Jacket

Back from

fireplace facing

2" or 4"

Flush with

fireplace facing

Figure 5 – Floor Protection

INSTALLATION RAISED 5” OR LESS

If non-combustible material floor protection needs to

be added in front of and level with the hearth

extension of the masonry fireplace (F = 5" or less),

an R-value equal to or greater than 1.00 is required

and should extend at least 23" (584 mm) in front of

the unit (B).

Figure 6 – Installation 5” or Less

INSTALLATION RAISED MORE THAN 5”

If the extension of the masonry hearth is raised

more than 5" (127 mm) from the floor protection, a

non-combustible material, without an R-value, must

extend at least 16" (406 mm in USA) or 18" (457

mm in Canada) in front of the unit.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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Figure 7 – Installation More Than 5”

R-VALUE

There are two ways to calculate the R-value of the

floor protection. First, by adding the R-values of

materials used, or by the conversion if the K factor

and thickness of the floor protection are given.

To calculate the total R value from R values of the

materials used, simply add the R-values of

materials. If the result is equal to or greater than the

R-value requirements, the combination is

acceptable. R-values of some selected materials

are shown below:

Table: Thermal Characteristics of Common Floor

Protection Materials*

MATERIAL

CONDUCTIVITY

(k) PER INCH

RESISTANCE (R)

PER INCH

THICKNESS

Micore

®

160

0.39

2.54

Micore

®

300

0.49

2.06

Durock

®

1.92

0.52

Hardibacker

®

1.95

0.51

Hardibacker

®

500

2.3

0.44

Wonderboard

®

3.23

0.31

Cement mortar

5.00

0.2

Common brick

5.00

0.2

Face brick

9.00

0.11

Marble

14.3 – 20.00

0.07 – 0.05

Ceramic tile

12.5

0.008

Concrete

1.050

0.950

Mineral wool

0.320

3.120

insulation

Limestone

6.5

0.153

Ceramic board

(Fibremax)

0.450

2.2

Horizontal still air**

(1/8")

0.135

0,920**

* Information as reported by manufacturers and

other resources

**Horizontal still air can’t be ‘stacked’ to accumulate

R-values; each layer must be separated with

another non-combustible material.

Example 1:

Required floor protection R of 1.00. Proposed

materials: four inches of brick and one inch of

Durock® board.

Four inches of brick (R = 4 x 0,2 = 0,8) plus 1 inch

of Durock® (R = 1 x 0.52 = 0.52).

0.8 + 0.52 = 1.32. This R value is larger than the

required 1.00 and is therefore acceptable.

Example 2:

In the case of a known K and thickness of

alternative materials to be used in combination,

convert all K values to R by dividing the thickness of

each material by its K value. Add R values of the

proposed materials as shown in the previous

example.

Example:

Common brick K value = 5

Thickness = 4"

R value = Thickness/K = 4/5 = 0.8

Durock K value =1.92

Thickness = 1"

R value = Thickness/K = 1/1.92 = 0.52

Total R value = .8 + 0.52 = 1.32

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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MINIMUM MASONRY OPENING

Refer to the Figure ‘Clearance to Combustibles’

MINIMUM MASONRY OPENING

J

23 5/16 " (592 mm)

K

28 7/8 " (733 mm)*

L

19 5/8 " (498 mm)**

* Where a fresh air intake is needed, we suggest

you add a minimum of 4’’ to the width of the

minimum masonry opening.

** If surround extension is used L = 17 5/8" or 15

5/8". If installed without the surround extension L =

19 5/8".

COMBUSTIBLE SURFACE REQUIRED

CLEARANCES

Note: Dimensions shown in the following figures are

from the body of the fireplace insert unless otherwise

indicated.

It is very important to follow minimum clearances for

chimney connectors to combustibles such as walls

and ceilings when installing the fireplace insert near

combustible surfaces.

The clearances shown in this section have been

determined by test according to procedures set out

in safety standards ULC S628 (Canada), UL1482

(U.S.A.) and UL737 (U.S.A.). When the insert is

installed so that its surfaces are at or beyond the

minimum clearances specified, combustible

surfaces will not overheat under normal and even

abnormal operating conditions.

NO PART OF THE INSERT MAY BE LOCATED

CLOSER TO COMBUSTIBLES THAN THE

MINIMUM CLEARANCE FIGURES GIVEN.

CLEARANCES

F

16" (406 mm)

G

9" (229 mm)

H

27" (686 mm)

I

27" (686 mm)

Q

84" (213 cm)

MAXIMUM THICKNESS

O

5" (127 mm)

P

12" (305 mm)

Figure 8 – Clearance to Combustibles

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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INSTALLING THE INSERT

1. Remove the contents of the firebox. This will

include the owner’s manual packet, 2 boxes of

soapstone for lining the firebox, spacers for the

floor stone, leveling bolts and enamel touch-up

if applicable.

2. Remove the front casting from the insert.

a. Remove the two screws visible below

the ash lip.

b. Tilt the frame up slightly, then LIFT the

frame up and off the hanger tabs on top

of fireplace insert.

c. Carefully remove the front casting from

the fireplace insert. It may be easiest

to open the door slightly and allow the

door handle to swing out of the way.

3. With two or more people, lift the insert and

remove it from the pallet.

4. Insert the leveling bolts. There are 2 nuts

welded to the outside of the firebox, one in each

of the lower rear corners. Thread the included

leveling bolts into the nuts.

5. If installing the optional steel surround, attach

the surround brackets according to the

instructions included with the steel surround

before placing the insert in the fireplace

opening.

6. Place the insert in the fireplace opening and

connect the liner to the inlet on top of the insert.

Follow the instructions in the Liner Installation /

Liner Connection section of this manual.

7. Level the insert. Adjust the bolts installed in

Step 4 to level the insert if needed.

8. (Optional) Install the Steel Surround following

the instructions included with that optional

accessory. Connect the surround to the

previously installed brackets.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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9. (Optional) Install the Lower Surround Panel

following the instruction included with that

optional accessory.

10. (Optional) Install the Surround Extension

following the instructions included with that

optional accessory. To install the surround

extension, the surround must be installed in

position 4” back from the front face of the insert.

The extension can also be as a 2” extension by

cutting the extension panels and installing the

surround 2” back from the front of the insert.

11. Install the blower switch plate on the front

casting:

a. Gently remove the blower switch

assembly from the lower left corner of

the insert. It is very important not to

disconnect the wires.

b. Attach the blower switch plate to the

lower rear left corner of the front

casting using the two screws in the

bosses.

12. Install the front casting following the procedure

from Step 2 in reverse order.

a. Carefully position the front casting on

the fireplace insert. Make sure the air

control handle passes through the

opening in the front casting below the

ash lip. It may be easiest to open the

door slightly to avoid hitting the door

handle.

b. Be careful not to pinch the blower

switch wires.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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c. LIFT the front casting up and onto the

tabs on top of fireplace insert. Guide

the hanger brackets onto the tabs and

let the front casting rest on the top edge

of the firebox.

d. Position the front casting by sliding it

left or right. Center the front casting

casting with the door. Carefully check

that the door can open fully without

making contact with the front casting.

e. Install the two screws below the ash lip.

These screws should pass through the

square holes in the hanger brackets

(attached to be front casting) and back

into the holes they were removed from

in Step 2. You may need to lift the front

casting slightly to engage the screws.

13. Install the soapstone in the firebox following the

diagram below.

a. Install the floor bricks first.

b. Install the 2 spacer channels along the

sides of the firebox.

c. Install the side stones, inserting the top

of each stone behind the retaining steel

then standing the stone against the

firebox wall.

d. Install the rear stones, inserting the top

of each stone behind the retaining steel

then standing the stone against the

firebox wall.

SIZE

QUANTITY

1

9" X 4.5" X 1.25"

14

2

9" X 4.25" X 1.25"

2

3

9" X 2" X 1.25"

4

6.5" X 4.5" X 1.25"

2

5

Spacer Channel

2

14. Inspect the installation.

a. The door opens fully and seals shut.

b. The air control moves left and right.

c. The blower turns on an off.

OUTSIDE AIR SUPPLY

(Optional Kit #94-53500)

You can connect an outside air source directly to

this fireplace insert using an optional outside air kit.

The advantage of providing outside air directly to

the fireplace insert is that the air used by the

fireplace insert for combustion is taken from outside

the residence rather than from within the room

where the fireplace insert is located.

The International Residential Code (IRC) does not

allow the outside air duct to terminate higher than

the appliance. Some building officials restrict

vertical rise in the duct’s termination. HearthStone

recommends the termination be at the same level,

or lower than the air intake on the fireplace insert.

Locate the termination of the duct on the outside

wall of the home in such a manner to avoid the

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

17

possibility of obstruction by snow, leaves or other

material.

Install the Outside Air Supply:

Using pliers, remove the rectangular knock-out

plate (A) located on the left or right side of the

convection air jacket. Choose the side that is best

for your installation.

Note: Only remove the knock-out that will be

connected to the fresh air inlet.

Figure 9 – Outside Air Inlet

Figure 10 – Outside Air Kit Detail

Then, install the fresh air kit adapter (B) using 4

screws (C). Secure the flexible pipe

1

(E) to the

adapter (B) using one of the adjustable pipe clamps

(D). Secure the other end of the pipe to the outside

wall termination (F) using the second adjustable

pipe clamp (D). The outside wall termination (F)

must be installed outside of the building.

1

The pipe must be HVAC type, insulated, and must

comply with ULC S110 and/or UL 181, Class 0 or

Class 1.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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The Venting System

GENERAL INFORMATION

The venting system, made up of the chimney and

the liner inside the chimney, acts as the engine that

drives your wood heating system. Even the best

insert will not function safely and efficiently as

intended if it is not connected to a suitable chimney

and liner system.

The heat in the flue gases that pass from the insert

into the chimney is not waste heat. This heat is

what the chimney uses to make the draft that draws

in combustion air, keeps smoke inside the insert

and safely vents exhaust to outside. The heat in the

flue gas can be seen as the fuel the chimney uses

to create draft.

BLOCK-OFF PLATE

To reduce the possibility of a cold air back draft

from the masonry chimney into the room, the

installation of a sheet metal block-off plate (A) is

recommended. When fabricating the block-off plate,

cut the pipe hole slightly larger than the liner

diameter and pass the liner through the hole. Install

the block-off plate and secure it with masonry nails.

Seal the joints between the plate and the chimney

with high temperature silicone and use stove

cement to seal between the pipe and the plate.

In Canada, the CSA B365 Standard permits ‘Roxul’

type wool to be stuffed around the liner as it passes

through the throat area as an alternative to a sheet

metal block-off plate. However, this method is less

efficient than using a plate.

Figure 11 – Block Off Plate 1

Figure 12 – Block Off Plate 2

SUITABLE CHIMNEYS

Your wood insert will provide optimum efficiency

and performance when connected to a 6-inch

diameter chimney liner. The connection to a

chimney having a diameter of at least 5 inches

(Canada only) is permitted, if it allows the proper

venting of combustion gases and that such

application is verified and authorized by a qualified

installer. Otherwise, the diameter of the flue should

be 6 inches. The reduction of liner diameter to less

than 6” should only be done if the total height of the

masonry chimney is greater than 20 feet.

LINER INSTALLATION

The use of a chimney liner (rigid or flexible) is

recommended to ensure the best performance. To

ensure an optimal draft, it is also strongly

recommend adding a minimum of 12" rigid liner

between the top of the masonry chimney and the

rain cap. In all cases, liners should be installed in

accordance with the liner manufacturer’s

instructions, including instructions for extension

above the masonry.

Use chimney liners listed UL 1777, ULC S635 or

CAN/ ULC S640.

In order to connect the insert to the liner, refer to

the section LINER CONNECTION.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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ATTENTION INSTALLER: When positioning the

unit in a fireplace opening prior to the flue

installation, install the insert into the opening until

the top lip of air jacket is flush with fireplace facing.

If lag bolts or anchors are to be used to secure the

insert, the hole locations should be marked with the

unit in place. Remove the insert and locate the

anchors.

Figure 13 – Liner Installation

LINER CONNECTION

Two options are possible to connect the liner to the

insert:

Liner Starter Adaptor

Two options are possible:

Install the chimney liner starter adapter, provided

with the chimney liner. Follow the chimney liner

starter adapter manufacturer's instructions.

In order to connect the chimney liner starter adapter

to the flue outlet, install three brackets with the

three screws, all provided in the user manual, on

top of the insert.

Figure 14 – Liner Connection

The long end of the brackets must be attached to

the insert. Insert the chimney liner into the flue

collar of the unit and secure the liner to the brackets

with three self-tapping screws (not included).

The dealer may offer a liner fastening system

(HearthStone accessory #94-67500), sold

separately. Follow the installation instructions

provided with the liner fastening system.

Figure 15 – Liner Fastening System

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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Liner Offset Adaptor

A liner offset adapter, sold separately, can also be

installed. This should only be installed if no other

option is possible and if the total height of the

fireplace and chimney is at least 20 feet. This kind

of adaptor is restricting the free flow of exhaust

gases and may result in smoke roll-out from the

insert when the door is open for reloading. When

installing a liner offset adapter, secure the three

brackets provided in the user manual on top of the

insert. The long end of the brackets must be

attached to the insert. Then, follow the instructions

in the manual provided with the liner offset adapter

kit.

Figure 16 – Offset Adaptor

MINIMUM CHIMNEY CLEARANCES

The top of the chimney should be tall enough to be

above the air turbulence caused when wind blows

against the house and its roof. The chimney must

extend at least 1 m (3 ft.) above the highest point of

contact with the roof, and at least 60 cm (2 ft.)

higher than any roof line or obstacle within a

horizontal distance of 3 m (10 ft.).

Figure 17 – Min. Chimney Height 1

Figure 18 – Min. Chimney Height 2

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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CHIMNEY LOCATION

Because the venting system is the engine that

drives the wood heating system, it must have the

right characteristics. The signs of bad system

design are cold back drafting when there is no fire

in the insert, slow kindling of new fires, and smoke

roll-out when the door is opened for loading.

When it is cold outside, the warm air in the house is

buoyant so it tends to rise. This tendency of warm

air to rise creates a slight pressure difference in the

house. Called ‘stack effect’, it produces a slightly

negative pressure low in the house (relative to

outside) and a slightly positive pressure zone high

in the house. If there is no fire burning in a heater

connected to a chimney that is shorter than the

warm space inside the house, the slight negative

pressure low in the house will compete against the

desired upward flow in the chimney.

There are two reasons why the chimney in the

house at right will cold backdraft when it is cold

outside and there is no fire burning in the insert.

First, the chimney runs up the outside of the house,

so the air in it is colder and denser than the warm

air in the house. And second, the chimney is shorter

than the heated space of the house, meaning the

negative pressure low in the house will pull outside

air down the chimney, through the insert and into

the room. Even the finest insert will not work well

when connected to this chimney.

Figure 19 – Chimney Location

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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SUPPLY OF COMBUSTION AIR

In Canada, wood inserts are not required to have a

combustion air supply from outside. Research has

shown that outside air supply do not compensate

for the depressurization of the house and may not

be sufficient to provide a supply of combustion air in

windy weather. However, to reduce the risks

against smoke spillage due to house

depressurization, a carbon monoxide (CO) detector

is required in the room where the insert is installed.

The CO detector will provide warning if for any

reason the wood insert fails to function correctly.

The safest and most reliable supply of combustion

air for a wood insert is from the room in which it is

installed. Room air is already preheated so it will

not chill the fire, and its availability is not affected by

wind pressures on the house. Contrary to

commonly expressed concerns, almost all tightly

sealed new houses have enough natural leakage to

provide a small amount of air needed by the insert.

The only case in which the wood insert may not

have adequate access to combustion air is if the

operation of a powerful exhaust device (such as a

kitchen range exhaust) causes the pressure in the

house to become negative relative to outdoors.

If an air intake is installed through the wall of the

house, its pressure can vary during windy weather.

If there are changes in wood insert performance in

windy weather, and in particular if smoke puffs from

the insert, the air duct should be disconnected from

the insert to determine if it is the cause of the

problem. In some windy conditions, negative

pressure at the duct weather hood outside the

house wall may draw hot exhaust gases from the

insert backwards through the duct to outdoors.

Check the outdoor air duct for soot deposits when

the full system is cleaned and inspected at least

once each year.

Figure 20 – Supply of Combustion Air

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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OPERATION

Once your Green Mountain Insert 70 is installed, you

are ready to light a fire.

Every installation, season’s firewood, and operator’s

technique varies. Learn how to use your fireplace

insert most efficiently for your installation. We can

give you the basic principles, but only you can

ensure maximizing the potential of your fireplace

insert while also operating it safely.

 WARNING: HOT WHILE IN OPERATION! KEEP

CHILDREN, PETS, CLOTHING AND FURNITURE

AWAY. CONTACT MAY CAUSE SKIN BURNS.

Read this entire chapter before lighting your first fire.

It explains the controls and features of your wood

fireplace insert, how to choose firewood, and how to

use your fireplace insert on a daily basis.

CONTROLS AND FEATURES

Before lighting any fires, become familiar with the

location and operation of your fireplace insert's

controls and features and learn how to use them

(See Figure 24). For your own safety, do not modify

these features in any way. We recommend you use

fireplace gloves when the fireplace insert is in

operation and hot.

Figure 21 - Controls & Features

FRONT DOOR HANDLE: The firebox door allows

you to load wood into your fireplace insert; a wood

handle operates the door. To open the door, pull up

on the handle and swing the door away from the

fireplace insert. To latch the door, push the door

tightly towards the firebox then continue to push the

handle in and down until it latches shut. Gently pull

on the door handle to make sure it is properly

latched.

PRIMARY AIR CONTROL: The primary air control

lever is located under the ash lip. The primary air

control allows you to regulate the amount of air

entering the firebox. Generally, the more air allowed

into the firebox, the faster the rate of burn and the

higher the heat output. Conversely, less air creates

a slower burn, with lower heat output. For maximum

airflow, pull the lever left as far as possible; move

the lever right as far as possible for minimum airflow

(does not close completely).

Figure 22 – Air Control

BLOWER OPERATION

A blower is already installed on this insert. It is

located underneath the insert, behind the front

casting. Its function is to increase airflow through

the heat exchanger and improve hot air circulation in

the room. When used regularly, the blower can

provide a small increase in efficiency, up to 2%.

However, the use of a blower should not be used as

a way to gain more output from an insert that is

undersized for the space it is intended to heat.

Ensure the blower cord is not in contact with any

surface of the insert to prevent electrical shock

or fire damage. Do not run cord beneath the

insert.

Alow the insert to reach operating temperature

(approximately one hour) before turning on the

blower, since increased airflow from the blower will

remove heat and affect the start up combustion

efficiency.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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The insert's blower assembly is equipped with a heat

sensor. Therefore, you can leave the switch in the

automatic position (3). The blower will start

automatically when the insert is hot enough and it

will stop when the insert has cooled down. You can

also set the switch to the manual position (1) to

operate the blower at any time. Select the position

(2) to manually stop the blower.

Figure 23 – Air Control

Figure 24 – Air Control

CHOOSING FIREWOOD

Burn only natural firewood (known as cordwood) in

the Green Mountain Insert 70 Model 8450 Wood

Heater. This fireplace insert is not designed to burn

other fuels.

 CAUTION: DO NOT USE CHEMICALS OR

FLAMMABLE FLUIDS TO START THE FIRE. DO

NOT USE CHARCOAL, PELLETS, COAL,

ARTIFICIAL LOGS OR ANY OTHER MATERIALS

AS FUEL; THEY ARE NOT SAFE. DO NOT BURN

GARBAGE OR FLAMMABLE FLUIDS.

 THE USE OF UNAUTHORIZED FUEL SUCH AS

COAL COULD PRODUCE HIGH LEVELS OF

CARBON DIOXIDE IN THE LIVING SPACE. AT

HIGH LEVELS CARBON DIOXIDE COULD RESULT

IN PERSONAL INJURY OR DEATH.

The quality of your firewood directly affects heat

output, duration of burn and performance of your

fireplace insert. Softwoods generally burn hotter and

faster, while hardwoods burn longer and produce

better coals. Density and moisture content are two

critical factors to consider when purchasing wood.

The following is a list of some wood species and

their relative BTU (British Thermal Unit) content. The

higher the BTU content, the longer the burn.

Firewood with higher BTUs is generally ideal for a

wood fireplace insert.

Wood Heat Value: Sorted By Btu Content

Common Name

Lb/ cord

MBTU/ cord

High

Osage Orange (Hedge)

4,728

32.9

Hickory, Shagbark

4,327

27.7

Hop Hornbeam (Ironwood)

4,267

27.3

Beech, Blue (Ironwood)

3,890

26.8

Birch, Black

3,890

26.8

Locust, Black

3,890

26.8

Hickory, Bitternut

3,832

26.7

Locust, Honey

3,832

26.7

Apple

4,100

26.5

Mulberry

3,712

25.8

Oak, White

4,012

25.7

Medium High

Beech, European

3,757

24

Maple, Sugar

3,757

24

Oak, Red

3,757

24

Ash, White

3,689

23.6

Birch, Yellow

3,689

23.6

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

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Medium

Juniper, Rocky Mtn

3,150

21.8

Elm, Red

3,112

21.6

Coffee tree, Kentucky

3.112

21.6

Hackberry

3,247

20.8

Tamarack

3,247

20.8

Birch, Gray

3,179

20.3

Birch, White (Paper)

3,179

20.3

Walnut, Black

3,192

20.2

Cherry

3,120

20

Ash, Green

2,880

19.9

Cherry, Black

2,880

19.9

Elm, American

3,052

19.5

Elm, White

3,052

19.5

Sycamore

2,808

19.5

Ash, Black

2,992

19.1

Maple, Red

2,924

18.7

Fir, Douglas

2,900

18.1

Medium Low

Boxelder

2,797

17.9

Alder, Red

2,710

17.2

Pine, Jack

2,669

17.1

Pine, Norway (Red Pine)

2,669

17.1

Pine, Pitch

2,669

17.1

Catalpa

2,360

16.4

Hemlock

2,482

15.9

Spruce, Black

2,482

15.9

Pine, Ponderosa

2,380

15.2

Low

Aspen, American

2,290

14.7

Butternut (Walnut, White)

2,100

14.5

Spruce

2,100

14.5

Willow

2,100

14.5

Fir, Balsam

2,236

14.3

Pine, White (Eastern,

Western)

2,236

14.3

Fir, Concolor (White)

2,104

14.1

Basswood (Linden)

2,108

13.8

Buckeye, Ohio

1,984

13.8

Cottonwood

2,108

13.5

Cedar, White

1,913

12.2

Moisture content also plays a key role in the

performance of your fireplace insert. Wood freshly

cut from a living tree (green wood) contains a great

deal of moisture. As you might expect, green wood

burns poorly. You must season green wood before

using it in your wood fireplace insert. To season

green wood properly, split, stack, and allow it to air

dry for a period of one year. Green wood may

provide less than 2000 Btu per pound, whereas dry

wood can provide up to 7000 Btu per pound.

Stack the firewood on skids or blocks to keep it off

the ground, cover only the top of the stack. Plastic or

tarps that cover the sides of the woodpile trap

moisture and prevent the wood from drying. As for

stacking, an old Vermonter said, "The spaces

between the logs should be large enough for a

mouse to get through, but not for the cat that's

chasing it."

 CAUTION: DO NOT STORE FIREWOOD WITHIN

THE FIREPLACE INSERT'S SPECIFIED

CLEARANCES TO COMBUSTIBLE MATERIALS.

BUILDING A FIRE

Once you understand the controls of your wood

fireplace insert and have the appropriate firewood,

you are ready to start a fire.

 WARNING: NEVER USE GASOLINE, GASOLINE-

TYPE LANTERN FUEL, KEROSENE, CHARCOAL

LIGHTER FLUID, OR SIMILAR LIQUIDS TO START

OR 'FRESHEN UP' A FIRE IN THIS HEATER.

KEEP ALL SUCH LIQUIDS WELL AWAY FROM

THE HEATER WHILE IT IS IN USE.

BREAKING IN YOUR WOOD FIREPLACE INSERT

It is imperative that your fireplace insert is "broken

in" gradually. Soapstone must be "seasoned"; over-

firing a new fireplace insert may cause soapstone to

crack or may damage other fireplace insert parts.

Natural moisture in the freshly quarried soapstone

must be driven out slowly to minimize the “shock” to

the stone of its first exposure to high firebox

temperatures. In addition, the asbestos-free furnace

cement must be cured slowly to ensure adequate

sealing and bonding.

When you light your first fires, the wood insert will

emit some smoke and fumes. This is normal “off-

gassing” of the paints and oils used when

manufacturing the wood insert. If you find it

necessary, open a few windows to vent your room.

The smoke and fumes will usually subside after 10

to 20 minutes of operation. The odor and smoke will

end once the fireplace insert is “cured”.

The first few fires of the season may produce other

odors from impurities that exist in the area

immediately surrounding the fireplace insert. Some

potential impurities are cleaning solvents, paint

solvents, cigarette smoke, and soot from scented

candles, pet hair, dust, adhesives, a new carpet, and

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

26

new textiles. These odors will dissipate over time.

You can alleviate these odors by opening a few

windows or otherwise creating additional ventilation

around your fireplace insert. If any odor persists,

contact your dealer or an authorized service

technician.

If you adhere to the operating procedures in this

manual, the steel, cast iron, and soapstone

components of your fireplace insert will give you

many years of trouble-free use. With use, the color

of the soapstone may change and small fractures

may appear on the surface. These changes do not

affect the function of the fireplace insert. If a panel

breaks completely, it must be replaced

Avoid the following conditions that can cause the

glass, soapstone, steel or cast iron pieces to break:

 Do not throw wood into the fireplace insert.

 Do not use the door as a lever to force wood into

the fireplace insert.

 Do not load wood encrusted with ice into a

burning fireplace insert - the thermal shock can

cause damage.

 Do not use a manufactured log grate or

otherwise support the fuel. Burn the fire directly

on the floor of the firebox.

BUILDING A BREAK IN FIRE

1) Open the bypass handle.Open the front door

and place five or six double sheets of tightly

twisted newspaper in the center of the firebox.

Arrange kindling in a crisscross pattern over the

newspaper. Kindling should be approximately

ten pieces, 1/2" (13 mm) in diameter and 10" to

16" (254 mm to 457 mm) long.

2) Fully open the primary air control by pulling the

control handle fully to the left.

3) Light the paper under the kindling. Leave the

door slightly ajar momentarily until the kindling

has started to burn and draft begins to pull.

4) Close the door and allow the fire to burn. Keep

the door closed while the fireplace insert is in

use.

5) KEEP A WATCHFUL EYE ON YOUR

FIREPLACE INSERT to maintain a steady, low-

heat fire. Your first fire should make the

fireplace insert warm but not hot to the touch.

Visible steam, or boiling moisture and hissing

indicate the soapstone is too hot. At most, a few

small chunks of wood should be added to the

fire to reach safe break-in temperatures.

6) Once the fireplace insert is warm but not hot to

the touch, close the primary air control by

pulling it fully to the right to allow the fire to die

out completely.

7) Let the fireplace insert return to room

temperature.

Your first fire and first fire each season thereafter

should be built and maintained as outlined above.

Your patience will be rewarded by a properly

seasoned fireplace insert.

 NOTE: The cool flue gas temperatures

present during the break-in procedure may

cause rapid creosote build-up. The door

glass may also get dirty. A good hot fire will

clean it. We recommend a visual inspection

(and cleaning if necessary) of your

stovepipe and chimney once the break-in

procedure is completed.

NORMAL OPERATION

BUILDING A FIRE FOR EVERYDAY USE

1) Open the front door and place five or six double

sheets of tightly twisted newspaper in the center

of the firebox. Arrange kindling in a tee-pee

configuration over the newspaper. Use

approximately 10 pieces of kindling, 1/2" (13

mm) in diameter and 10" to 16" (254 mm to 406

mm) long.

2) Fully open the primary air control by pulling the

lever completely left.

3) Light the paper under the kindling. Leave the

front door slightly ajar momentarily until the

kindling begins to burn and draft begins to pull.

4) Close the door and allow the fire to burn.

5) Once the kindling is burning, open the front door

and add logs, small at first, to build the fire up.

Ensure you keep the logs away from the glass in

front in order for the air-wash system to work

properly. Keep the front door closed while the

fireplace insert is in use.

CAUTION: DO NOT BUILD THE FIRE TOO CLOSE

TO THE GLASS. KEEPING THE FIRE TOWARDS

THE CENTER OF THE FIRE BOX WILL KEEP

COALS FROM BUILDING UP AGAINST THE

GLASS DURING RELOADING.

6) Use the primary air control to regulate the

desired rate of burn. Pull the handle left for a

higher burn rate, and pull the handle right for a

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

27

lower burn rate. The air control does not close

completely.

Note: When opening the front door to reload or re-

arrange logs, it is advisable to open the door just a

crack, pause for a moment then open the door

completely. This procedure allows the firebox to

clear of smoke before the door is open fully. In

addition, reloading on a bed of hot, red coals

reduces smoking time and brings fresh fuel up to a

high temperature rapidly. When reloading the

fireplace insert, try to keep an open path behind the

Lower Primary Air Opening (LPAO). It is helpful to

leave a small valley in the coal bed behind the LPAO

to insure faster re-lighting.

BURN RATE

This wood heater has a manufacturer-set

minimum low burn rate that must not be altered.

It is against federal regulations to alter this

setting or otherwise operate this wood heater in

a manner inconsistent with operating

instructions in this manual

LOW BURN: Move the air control lever all the way

to the right. (See figure 24). This closes the air

shutter to its minimum opening. A low burn rate over

extended periods is not advisable as it can promote

the accumulation of creosote. Inspect the venting

system frequently if using low burn rates

consistently.

MEDIUM LOW BURN: With the primary air control

in the low position, pull the air control left (a little less

than 1/2”). A medium-low burn rate is the typical

setting and is preferable if the fireplace insert is

unattended. At this burn rate, a little goes a long

way.

MEDIUM HIGH BURN: With the primary air control

in the low position, pull the air control left (a little less

than 1”)

HIGH BURN: Completely open the primary air

control by moving it all the way left. Fully load the

firebox with wood on a bed of hot coals or on an

actively flaming fire. To minimize creosote

accumulation, run the fireplace insert on high once

or twice daily for 35 to 45 minutes to fully heat the

stovepipe and chimney.

CAUTION: Do not burn fuel other than cordwood in

your fireplace insert.

OVER-FIRE CAUTION

Over-firing means the fireplace insert is operating at

temperatures above normal temperatures reached

during High Burns outlined in the BURN RATE

section. Carefully avoid over-firing, as it will damage

the fireplace insert. Symptoms of chronic over-firing

can include warped components, short burn times, a

roaring sound in the fireplace insert or chimney, and

discoloration of the finish. A properly installed

fireplace insert using fuel and following operating

procedures as outlined in this manual should not

over-fire.

Excessive draft, inappropriate fuel, and operator

error can cause over-firing. Correct an over-fire

situation as follows:

 EXCESSIVE DRAFT: Contact your local dealer

to have a draft reading taken. Any draft in

excess of 0.1 WC requires a damper in the

stovepipe. Some installations may require more

than one damper.

 INAPPROPRIATE FUEL: Do not burn coal; kiln

dried lumber, wax logs, compressed wood,

highly volatile fuels or combustibles, or anything

other than natural cordwood.

 OPERATOR ERROR: Ensure all the gaskets

are in good condition. Replace worn out or

compressed gaskets. Only burn the fireplace

insert with the door in the closed position, or

completely open when using the fireplace

screen.

If you suspect your insert is over-firing, discontinue

use and contact your dealer immediately. Damage

caused by over-firing is not covered by your

warranty. Results of over-firing can include warped

or burned out internal parts, cracked refractory

panels, discolored or warped external parts, and

damaged finish.

 ANY SIGNS OF OVER-FIRING WILL VOID YOUR

WARRANTY!

REMOVAL AND DISPOSAL OF ASHES

You can leave a thin layer of ashes in the firebox if

preferred. Allow fire to die down or go out

completely. It is important to prevent ashes from

building up around the front door opening or they will

spill out, or they can pack into the gasket channel

and prevent proper sealing. To remove ashes, use a

fireplace shovel. Avoid removing large live coals by

pushing them to the side and removing only the finer

ash with a shovel.

Disposal of ashes - Ashes should be placed directly

into a metal container with a tight fitting lid. Do not

place any other items or trash into the metal

container. Do not pour water into the container.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

28

Replace the container’s lid and allow the ashes to

cool. Never place the ash disposal container on a

combustible surface or vinyl flooring, as the

container could be hot!

Pending disposal, place the closed ash container on

a noncombustible floor or on the ground outside,

well away from all combustible materials, liquid fuels,

or vehicles. Retain ashes in the closed container

until all coals thoroughly cool.

If the ashes are disposed of by burial in soil or

otherwise locally dispersed, they should be retained

in the closed container until all cinders have

thoroughly cooled.

NEVER place ashes in wooden or plastic containers,

in trashcans with other trash, or in paper or plastic

bags, no matter how long the fire has been out.

Coals within a bed of ashes can remain hot for

several days once removed from the firebox.

FIRE SCREEN

(Optional Kit #94-69500)

Install the optional fire screen:

Open the door.

Figure 25 – Open Door

Hold the fire screen by the two handles and bring it

close to the door opening.

Figure 26 – Install Fire Screen

Lean the upper part of the fire screen against the top

door opening making sure to insert the top fire

screen brackets behind the primary air deflector.

Lift the fire screen upwards and push the bottom

part towards the insert then let the fire screen rest

on the bottom of the door opening.

Figure 27 – Install Fire Screen 2

Warning: Never leave the insert unattended while

in use with the fire screen.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

29

Maintenance

CREOSOTE FORMATION & REMOVAL

When wood burns slowly at low temperatures, it may

produce tar and other organic vapors, which

combine with expelled moisture to form creosote.

These creosote vapors condense in the relatively

cool chimney flue of a slow-burning fire. As a result,

creosote residue accumulates on the flue lining.

When ignited, this creosote makes an extremely hot

fire, which may damage the chimney or even destroy

the house. When burning wood, inspect the chimney

connector and chimney at least once every two

months during the heating season to determine if

there is a creosote buildup.

If a creosote build-up occurs, inspect the stovepipe

connector and chimney more often, at least monthly

during the heating season to monitor the

accumulation. If a creosote residue greater that 1/4"

(6 mm) accumulates, remove it to reduce the risk of

a chimney fire.

PREVENTION

Burn the fireplace insert with the primary air control

fully open for 35 - 45 minutes daily to burn out

creosote deposits from within the fireplace insert and

the venting system.

After reloading with wood, burn the fireplace insert

with the primary air control fully open for 15 to 20

minutes. This manner of operation ensures early

engagement of the secondary combustion system

that minimizes creosote buildup in the chimney.

If your glass always remains dirty, your operating

temperatures are too low or your wood is wet;

therefore, there is a higher risk of creosote buildup.

Inspect the venting system at the fireplace insert

connection and at the chimney top. Cooler surfaces

tend to build creosote deposits faster, so it is

important to check the chimney at the top (where it is

coolest) as well as from the bottom near the

fireplace insert.

CLEANING

Remove accumulated creosote with a cleaning

brush specifically designed for the type of chimney

in use. We recommend you use a certified chimney

sweep to perform this service. Contact your dealer

for the name of a certified chimney sweep in your

area (your dealer may be a certified sweep!).

We recommend that before each heating season

you have the entire system professionally inspected,

cleaned and repaired, if necessary.

GASKETS

Replace door gasket material every two to three

seasons, or whenever it becomes deteriorated or

loose, depending on fireplace insert use. If the door

seal leaks, a new gasket will ensure a tight seal and

improve fireplace insert performance.

We recommend you only use HearthStone

replacement gaskets when you need to replace your

door gasket. Contact your dealer for a gasket kit that

includes instructions, and the gasket for your

fireplace insert.

GLASS

The glass used in our fireplace inserts is actually not

plain glass, but a tough, clear ceramic material

capable of operating at temperatures up to 2300° F.

Do not operate the fireplace insert with a broken

door glass. Do not abuse the front door by striking or

slamming.

When necessary, clean the glass. For the inside

surface of the glass, we recommend using a damp

paper towel dipped in white ash. Rub the inside of

the glass with a circular motion. When all the

deposits are removed, clean up with commercial

stove glass cleaners, which are available from your

local dealer. Use this type of cleaner for the outside

surface as well. Never attempt to clean the glass

while the fire is burning or while the glass is hot.

Remove deposits by following the instructions

provided with the cleaner. Wipe the cleaner off with

a soft cloth, or black & white newsprint.

Important: scratching or etching the glass

will weaken the integrity of the glass. Do not

use a razor blade, steel wool, or any other

abrasive material to clean the glass. Use a

cleaner specifically manufactured for

woodstoves only.

The front door glass is a ceramic, thermal shock-

resistant glass, made specifically for use in

woodstoves. Do not use any replacement glass

other than the ceramic glass manufactured and

supplied for use in this wood fireplace insert.

Replacement glass is available through your local

dealer.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

30

Replace the door glass immediately if broken or

chipped. Contact your local dealer for replacement

glass. The glass kit includes instructions and

everything needed for the repair. If you replace the

glass yourself, wear work gloves and safety glasses.

GLASS REPLACEMENT PROCEDURES

Required Glass Kit: Part Number: 96-58405

 WARNING: DO NOT OPERATE THIS APPLIANCE

WITH THE GLASS PANEL REMOVED, CRACKED,

OR BROKEN. DO NOT SUBJECT THE DOOR TO

ABUSE, SUCH AS STRIKING OR SLAMMING

SHUT. ONLY A QUALIFIED SERVICE PERSON

SHOULD REPLACE THE GLASS PANEL.

1. Follow the instructions included with the

replacement glass kit.

2. Remove the front casting.

a. Remove the two screws below the ash

lip, keep these for re-installing

b. Lift the front casting up and off the tabs

at the top of the firebox face, set aside.

3. Remove the door.

a. Use two people to remove the door.

b. In an open position, remove the lower

hinge from the door, 2 socket head cap

screws

c. Lift the door off of the upper hinge, save

the spacer.

4. Remove the screws from the glass clips (use

penetrating oil if necessary) – Set aside for

reinstallation.

5. Carefully lift the damaged glass off the door and

discard.

6. Remove any remaining glass and old gasket

material.

7. Clean the screw holes and place a small amount

of anti-seize compound in each one.

8. Install a new glass gasket in the glass gasket

groove.

9. Place the new glass onto the door.

a. Place the glass with the glossy side

facing out. (screen printed side in)

b. Align the screen printed arch with the

arch of the window opening.

10. Important! Center the glass and ensure that

the edges of the glass are parallel with the

edges of the opening.

11. Screw the glass retainer clips with the glass

pads back on the door using a crisscross

pattern. Tighten the screws no more than 1/8

th

of

a turn after they seat. The glass will break at this

point if not positioned correctly.

12. Apply a light film of anti-seize lubricant on the

door’s hinge pins if needed.

13. Install the door, following step 3 in reverse.

Note: use 2 people to install the door.

14. After 5 or 6 fires, check the glass retainer

screws, and retighten if necessary.

Figure 28 – Glass Assembly

BLOWER INSTALLATION / REPLACEMENT

1. Loosen and remove two screws below the ash

lip of the face plate.

2. Carefully remove the front casting from the

fireplace insert. Tilt the frame up slightly, then

LIFT the frame up and off the hanger tabs on top

of fireplace insert. It may be easiest to open the

door slightly and allow the door handle to swing

out of the way.

Figure 29 – Remove Front Casting

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

31

3. Slightly loosen the 4 wing nut (C) then pull the

blower assembly towards you to remove it from

the convection air jacket. Make sure to

disconnect the wiring as it is accessible.

Figure 30 – Loosen Blower Assembly

4. Carefully remove the blower motor assembly

from the fireplace insert. Be sure to disconnect

the electrical switch from the cast iron frame

once removed, being careful not to pull on the

wires or terminals. The switch plate is removed

by way of two fasteners on the inside-left of the

iron frame as shown.

Figure 31 – Remove Blower Assembly

Figure 32 – Remove Switch Plate

Figure 33 – Remove Switch Plate

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

32

DOOR ADJUSTMENT

In order for the insert to burn at its best efficiency,

the door must provide a perfect seal with the firebox.

The gasket should be inspected periodically to

insure a good seal.

To improve the door seal, replace the gasket using

Kit# 94-58500.

REPLACING THE REFRACTORY STONE

1. Allow the insert and ashes to fully cool.

2. Open the front door of the insert and fully

clean any ash in the firebox.

3. Remove the rear stones first.

4. Remove the side stones second.

5. Remove the bottom stones last.

6. Installation is the reverse of disassembly.

Make sure that the top edges of the stones

are behind the retaining steel pieces.

Figure 34 – Refractory Stone

SIZE

QUANTITY

1

9" X 4.5" X 1.25"

14

2

9" X 4.25" X 1.25"

2

3

9" X 2" X 1.25"

4

6.5" X 4.5" X 1.25"

2

5

Spacer Channel

2

INSTALLATION OF SECONDARY AIR TUBES AND

BAFFLE

1. Starting with the rear tube, lean and insert the

right end of the secondary air tube into the rear

right channel hole. Then lift and insert the left

end of the tube into the rear left channel.

Figure 35 – Secondary Air Tubes 1

2. Align the notch in the left end of the tube with

the key of the left air channel hole. Using a

« Wise grip » hold the tube and lock it in place

by turning the tube as shown in DETAIL A.

Make sure the notch reaches the end of the key

way.

Figure 36 – Secondary Air Tubes 2

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

33

3. Repeat steps 1 and 2 for the two tubes in the

back then install the baffle before installing the

two front tubes.

4. To remove the tubes use the above steps in

reverse order.

Figure 37 – Secondary Air Tubes 3

Figure 38 – Secondary Air Tubes 4

Note that secondary air tubes (B) can be replaced

without removing the baffle board (A).

REMOVAL INSTRUCTIONS

For the purpose of inspecting the insert itself or the

fireplace, your insert may need to be removed. To

remove your insert follow these instructions:

1. Remove the front casting assembly (A)

2. If necessary, remove blower (B)

3. Remove the screws that secure the chimney

liner to the fixation brackets (C).

4. Unscrew the leveling bolts (D) located on each

side of the insert.

5. Pull-out the insert from the fireplace opening to

perform the maintenance work.

Figure 39 – Insert Removal

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

34

Illustrated Parts List

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

35

IMPORTANT: THIS IS DATED INFORMATION. When requesting service or replacement parts for your insert,

please provide the model number and the serial number. We reserve the right to change parts due to

technology upgrade or availability. Contact an authorized dealer to obtain any of these parts. Never use

substitute materials. Use of non-approved parts can result in poor performance and safety hazards.

#

Item

Description

Qty

1

AC01315

RIGID FIRESCREEN

1

2

30569

ROUND WOODEN HANDLE BLACK

2

3

2410-520

FRONT CASTING, GMI70

1

4

5450-012

HANGER, FRONT CASTING, LOWER

2

5

5450-013

HANGER, FRONT CASTING, UPPER LEFT

1

6

5450-014

HANGER, FRONT CASTING, UPPER RIGHT

1

7

2410-510

DOOR, GMI70

1

8

5450-024

HINGE WITH PIN, DOOR, UPPER

1

9

5450-026

HINGE WITH PIN, DOOR, LOWER

1

10

3030-069

GLASS, 21.25”C11.94”

1

11

94-5950510

SURROUND LOWER PANEL, 42.25” X 5.25”

1

12

94-5950110

SURROUND, STEEL, 42.25” X 31.25”

1

13

94-5950010

SURROUND EXTENSION, 2” – 4”

1

14

5021-060

GLASS CLIP

6

15

3120-021

GASKET, GLASS CLIP

6

16

4500-2105

SCREW, MACHINE, 10-24 X 3/8” UND-CUT, FLAT, PH

6

17

30094

HEX SCREW WASHER HEAD 1/4-20 X 3/4" F ZINC TYPE

10

18

30187

STAINLESS WASHER ID 17/64" X OD 1/2"

3

19

PL65233-01A

LATCH SHIM

1

20

PL65234-01A

DOOR LOCK

1

22

94-71500

HANDLE REPLACEMENT KIT

1

23

5450-020

DOOR LATCH

1

24

5450-022

ROLLER, LATCH

1

25

4300-0701

CLEVIS PIN WITH C-CLIPS

1

26

4700-0790

SPACER, DOOR LATCH, BRASS

2

27

4600-0800

WASHER FLAT, 5/16, USS, 7/8OD, BLACK

1

28

5240-138

SPRING, LATCH, WOOD STOVE

1

29

2010-254

HANDLE CRANK, CAST IRON

1

30

4500-2976

SET SCREW, 5/16-18X38”, HALF DOG

1

31

3900-179

WOOD HANDLE

1

32

4600-0400

LOCK WASHER, ¼, SPLIT

2

33

4500-1680

SCREW, MACHINE, ¼-20 X 3-1/4”, ROUND, SLOT

1

34

5450-010

DOOR HINGE, UPPER

1

35

5450-011

DOOR HINGE, LOWER

1

36

4700-0850

SPACER, HINGE

1

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

36

#

Item

Description

Qty

37

4500-2114

MACHINE SCREW, 10-24 X 3/8”, PAN, PH, BLACK

2

38

3110-066

GASKET ROPE, 5/8”, MED DENSITY, BLACK, 7’

1

39

3110-056

GASKET ROPE, ¼”, BLACK, ADHESIVE, 6’

1

40

4500-0700

CAP SCREW, ¼-20 X 5/8”, HEX, GRADE 5, BLACK OXIDE

8

41

5400-2132

SOCKET HEAD CAP SCREWS, 10-24 X ½”, BLACK

4

42

30021

SELF TAPPING SCREW 8-32 "F" TYPE X 7/16" FLAT HEAD PHILLIPS BLACK

2

43

30764

WOODEN AIR CONTROL HANDLE

1

44

30506

SCREW PAN TORX TYPE F 1/4-20 X 1" BLACK

1

45

30206

ZINC WASHER 5/16"ID X 3/4"OD

1

46

SE65842

AIR CONTROL DAMPER ASSEMBLY

1

48

30060

THREAD-CUTTING SCREW 1/4-20 X 1/2" F HEX STEEL SLOT WASHER C102 ZINC

5

49

AC01298

5"Ø FRESH AIR INTAKE KIT OVAL

1

50

30337

SQUARE HEAD SET SCREW 1/2-13 X 1-3/4"

2

51

5450-100

LATCH AND HINGES ACCESS PANEL

2

52

30131

BLACK METAL SCREW #10 X 1/2" TYPE "A" PAN QUADREX

4

53

PL34052

LINER FIXATION BRACKET

3

54

SE65746

FAN ASSEMBLY

1

55

44092

3 POSITION ROCKER SWITCH

1

56

5450-015

SWITCH BRACKET

1

57

PL65629

JUNCTION BOX COVER

1

58

60013

POWER CORD 96" X 18-3 type SJT

1

59

PL65627

JUNCTION BOX

1

60

30413

SNAP BUSHING

1

61

PL65626

FAN WIRE GUIDE

1

62

30484

WING NUT 1/4-20

4

63

44028

CERAMIC THERMODISC F110-20F

1

64

PL65632

THERMODISC CASING

1

65

PL65746

FAN BOTTOM FIXATION PLATE

1

66

44075

TANGENTIAL BLOWER 1800 115V-60hZ-30W (S) 90 CFM

1

67

PL65748

FAN PROTECTION COVER

1

68

SE45929

INSTRUCTION MANUEL KIT MATRIX INSERT

1

70

21387

TOP AIR DEFLECTOR INSULATION

1

71

PL65505

TOP AIR DEFLECTOR PROTECTOR

1

72

PL30583

FLOOR BRICK RETAINER / SPACER

2

73

9450-00 (KIT)

SOAPSTONE: 6 1/2" X 4 1/2'' X 1 1/4''

2

74

9450-00 (KIT)

SOAPSTONE: 4 1/2'' X 9'' X 1 1/4''

14

75

9450-00 (KIT)

SOAPSTONE: 4 1/4" X 9'' X 1 1/4''

2

76

9450-00 (KIT)

SOAPSTONE: 2" X 9" 1 1/4"

4

77

PL65514

SECONDARY AIR TUBE

4

78

21389

C-CAST BAFFLE 20" X 12 1/2" X 1 1/4"

1

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

37

REPLACEMENT KITS & OPTIONAL ACCESSORIES

Refer to the Illustrated Parts list for further detail about insert components, available online at

www.hearthstonestoves.com.

PART #

DESCRIPTION

94-53500

OUTSIDE AIR KIT

94-69500

FIRE SCREEN INSERT

94-5950010

SURROUND EXTENSION

94-5950510

SURROUND LOWER PANEL

94-5950110

STEEL SURROUND

94-58500

GASKET KIT: DOOR AND DOOR GLASS

94-58505

GLASS KIT: GLASS AND GASKET

94-71500

HANDLE KIT, FULL ASSEMBLY

94-73500

FRONT DOOR LATCH KIT

94-76500

BAFFLE KIT

94-57500

BLOWER KIT

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

38

Troubleshooting

COMMON ISSUES

Virtually all wood insert operators experience basic

common problems at one time or another. Most are

correctable and generally require only a minor

adjustment of the insert, installation, or operating

technique. In cases where weather conditions

dramatically affect insert performance, the problems

are typically temporary and resolve themselves once

the weather changes.

Keep in mind that your house itself regulates

room/house temperatures. How well the walls, floors

and ceilings are insulated, the number and size of

windows, the tightness of exterior doors, and the

construction or style of your house (vaulted ceilings

or other open spaces which collect large percentages

of heat, ceiling fans, etc.) all are determining factors

of room temperature.

Your Insert's performance is also greatly dependent

on its installation. One common cause of poor

performance is inadequate draft. An oversized

chimney flue is commonly the cause. Oversized flues

result in decreased vacuum, which prevents the

smoke from rising out the chimney. Oversized flues

are also more difficult to heat effectively, especially

when burning a high efficiency insert like the Green

Mountain Insert 70. Cool flue temperatures inhibit the

establishment of a strong draft (and encourage

accumulation of creosote). The lack of a strong draft

will cause the fire to die down and may even force

smoke into the room. If your chimney is the proper

size and a strong draft is not easily established, there

is the possibility the chimney is just too cold. Again,

hot chimneys promote a stronger draft. Other draft

issues and guidelines are as follows:

1. AN "AIRTIGHT" HOUSE:

a. Inadequate infiltration air supply in a

super-insulated or especially well sealed

home.

b. Air starvation exacerbated by exhaust

fans, such as clothes dryers, bathroom vent

fans, or cook stove exhaust fans.

2. TALL TREES OR BUILDINGS:

a. These obstructions, in close proximity to

the top of the chimney can cause chronic or

occasional downdrafts.

b. Consider the placement of other objects

when selecting a site for a new chimney.

3. WIND VELOCITY:

a. Strong, steady winds generally create a

strong (better) draft.

b. “Gusty" wind conditions may cause erratic

downdrafts. Strong winds can produce a

negative pressure condition in the upwind

side of a structure.

4. BAROMETRIC PRESSURE:

a. Chimney drafts are typically sluggish on

balmy, wet or muggy days (low or falling

barometric pressure). This is generally self-

correcting as the weather changes.

5. BRISKNESS OF FIRE:

a. The hotter the fire, the hotter the chimney

and, therefore, the stronger the draft.

6. SEASONAL FACTORS:

a. Early fall and late spring are generally

difficult seasons in which to establish proper

drafts. The colder the outside air is (relative

to room temperatures) the stronger the draft.

7. OPERATING THE FIREPLACE INSERT:

a. There are days when a draft is just not

easily established. As outlined above,

seasonal factors or a cold chimney may be

the cause.

b. Starting the fire using small kindling and

small wood pieces to obtain a quick, hot fire.

Tend the fire frequently with small pieces

until the chimney is hot and the draft is well

established.

c. Briefly partially open a window in the room

with the insert to help establish a draft

quickly.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

39

Troubleshooting Guide

PROBLEM

POSSIBLE CAUSE

SOLUTIONS

INSERT SMOKES

Operating Technique

Fully open the primary air control one minute before opening doors,

and ensure the bypass is open before opening door.

Cold Chimney or reverse

draft

Preheat the chimney when first starting a fire. Briefly open a window in

the room containing the insert.

Blocked Chimney

Examine the chimney and stovepipe for blockage or creosote

accumulations.

Oversized Chimney

Reline the chimney to the appropriate diameter

Undersized Chimney

Install a draft inducer or replace the chimney.

Chimney Too Short

Lengthen the chimney.

Air Infiltration Into The

Chimney

Seal chimney connections and openings. Check clean-out doors.

Not burning proper fuel

Ensure cordwood is seasoned and dry.

More Than One Appliance

Connected to the Flue

Disconnect all other appliances and seal openings.

BACK-PUFFING

OR GAS

EXPLOSIONS

Operating Technique

Fully open the primary air control one minute before opening the door

and keep it fully open for a few minutes after reloading. Ensure the

bypass door is open before opening the door

Extra Low Burn Rate

Burn the insert at a higher burn rate.

Chimney Down-draft

Install a chimney cap.

Excessive Ash Build-up

Empty the ash pan more frequently. Increase efficiency of burns, and

avoid using poor quality or green wood.

UNCONTROLL-

ED OR SHORT

BURN

Unsealed or Open Door

Close the door tightly or replace the gaskets.

Air leakage around glass gasket – replace gasket

Excessive Draft

Check the installation. Operate at LOW BURN. Install stovepipe

damper. Draft in excess of 0.1 wc should be corrected with a stovepipe

damper(s)

Extra Long Chimney

Shorten the chimney. Install stovepipe damper(s).

Oversized Chimney

Reline the chimney to the proper diameter.

High Winds or Hilltop

Location:

Install a chimney cap.

INSUFFICIENT

HEAT

Poor Quality, low Btu

content, or Green Wood

Use only air-dried wood, preferably dried at least one year. Use a wood

with a high Btu content if available.

Low Burn Rate

Operate the insert at a higher burn rate.

Cold Exterior Chimney

Reline or insulate the chimney.

Leaky Stovepipe or

Chimney

Check the installation. Replace with a pre-fabricated insulated chimney

system or a properly sized masonry chimney.

Too Much Heat Loss From

House

Add insulation, use energy efficient windows, or caulk windows, and

seal openings in home.

Excessive Ash Build-up

Empty the ash pan more frequently. Increase efficiency of burns, and

avoid using poor quality or green wood.

BLISTERING OF

FINISH

Operating Technique

Do not over-fire the insert. Monitor insert temperatures. Use seasoned

wood only.

Excessive Draft

Check the DRAFT. A damper may be required. Operate the insert at a

LOW BURN range.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

40

Safety Label

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

41

Limited Warranty

These warranties give you specific legal rights. You may also have other rights, which vary from State

to State.

HearthStone Quality Home Heating Products, Inc. (HearthStone) warrants to the original retail purchaser only

(the “Original Purchaser”) the new appliance manufactured by HearthStone, purchased by the Original

Purchaser and installed by an authorized HearthStone dealer or their designated representative against any of

the occurrences listed in this document that result from defects in material or workmanship. This warranty is not

transferrable. All obligations of HearthStone under this document commence on the date of the Original Invoice

(the “Purchase Date”). The term “Limited Lifetime” is defined as 10 years from the beginning of warranty

coverage.

HearthStone appliances are designed to be operated only with the fuels listed in your owner’s manual.

Insert components Limited Warranty

Warranty

Period

Wood

Gas

Pellet

Covered Components

Limited Lifetime

X

Stone

X

Cast iron not listed elsewhere

X

Clean burning air supply system*

5 Year

X

Door handles and latches

X

Steel Components and Firebox

X

Burner and logs

3 Year

X

Burn Pot and Baffles

2 Year

X

Appliance Electrical and Gas

Components

X

Refractory, Vermiculite Panels, Baffles

1 Year

X

Enamel finish against peeling or fading

X

Accessories

X

Glass

X

Ash Grate

X

All components not listed elsewhere

Any parts repaired or replaced during the limited warranty period will be warranted under the terms of the limited

warranty for a period not to exceed the remaining term of the original limited warranty or one year, whichever is

longer.

Parts: HearthStone will replace through an authorized dealer, defective parts covered by the foregoing warranty

at no charge.

Labor: Within the first (1st) year after the Purchase Date, HearthStone will pay for warranty labor performed by

an authorized Dealer at HearthStone’s published labor rates in effect at the time the labor is performed only if

the appliance is installed by an authorized dealer or their designated representative. Otherwise or thereafter, the

Original Purchaser is responsible for the cost of labor.

Shipping cost for parts: Within the first ninety (90) days after the Purchase Date, HearthStone will pay for the

shipping of appliance parts covered by any of the foregoing warranties to and from HearthStone or an

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

42

authorized Dealer, as the case may be. Thereafter, the Original Purchaser is responsible for all shipping costs

related to shipping appliance parts to and from HearthStone or an authorized Dealer, as the case may be.

Shipping cost for the appliance: Within the first (1st) year after the Purchase Date, if the Original Purchaser is

instructed to return the appliance to HearthStone or an authorized Dealer for repair, HearthStone will pay fifty

percent (50%) and the Original Purchaser will pay fifty percent (50%) of the shipping costs related to shipping

the appliance to and from HearthStone or an authorized Dealer, as the case may be. Thereafter, the Original

Purchaser is responsible for one hundred percent (100%) of all of the shipping costs related to shipping the

appliance to and from HearthStone or an authorized Dealer, as the case may be. Notwithstanding any other

provision of this document, in no event will HearthStone pay for any Dealer fees or other fees for pick up or

delivery of the appliance returned for repair; the Original Purchaser shall be responsible for any such fees.

EXCLUSIONS & CONDITIONS

The warranties contained in this document do not cover, nor is HearthStone responsible for:

1. Damages resulting from:

a. Failure to install, operate, or maintain the appliance in accordance with the owner’s manual, operating

instructions, installation instructions, or safety rating label provided with the appliance.

b. Over-firing the appliance. Over-firing can be identified by, but not limited to, warped cast iron or steel,

rust colored cast iron, bubbling, cracking and discoloration of steel or enamel finishes.

c. Failure to install the appliance in accordance with all national or local building codes.

d. Shipping or improper handling.

e. Improper operation, abuse, misuse, continued operation with damaged, corroded, or failed components,

accident, or improper/incorrect service or repairs.

f. Environmental conditions, inadequate ventilation, negative pressure, or improper drafting caused by

tightly sealed constructions, insufficient make-up air supply, or air handling devices such as exhaust

fans, forced air furnaces, or other such causes.

g. Damage caused by direct exposure to water.

h. Use of fuels other than those specified in the owner’s manual.

I. Installation or use of components not supplied with the appliance, or any other components not

expressly authorized and approved by HearthStone.

J. Modifications of the appliance not expressly authorized and approved by HearthStone in writing

K. Interruptions or fluctuations of electrical power supplied to the appliance.

2. All stones are warranted against cracking or breakage due to thermal stress, excluding surface and hairline

cracks and scratches that do not affect the operation, or safety of the appliance.

3. Repair or replacement of wear parts. Such parts that are subject to normal wear and tear during the

warranty period such as paint, gaskets, baffles, refractory materials, ash grates, and glass.

4. Damage resulting from installation, modification, alteration, repair or service of the appliance by any party

other than an authorized HearthStone dealer (a “Dealer”) or their designated representative, or

HearthStone.

5. Damage due to water or condensation due to installation of the appliance in a high moisture area.

6. Damage due to installation of the appliance in an atmosphere contaminated by damaging chemicals,

including but not limited to chlorine, fluorine or salts.

7. Scratches on glass, enameled surfaces or stones due to mechanical abrasion.

8. Noise caused by expansion or contraction caused by the heating and cooling of the appliance.

9. Odors caused by the heating of the appliance, or surrounding materials

10. Consequential damage caused by leaking of condensate during startup

11. A defect in any part of the appliance if the Original Purchaser fails to comply with HearthStone’s or a

Dealer’s request to ship the part or the appliance to HearthStone or a Dealer, as the case may be.

12. Replacement stones and enameled parts are taken from current stock, and may not match originals in color,

grain, or pattern. HearthStone will supply replacement parts for discontinued parts in finishes or colors as

available, or at their discretion.

13. HearthStone’s obligation under this warranty does not extend to the appliance’s ability to heat the desired

space. Information is provided to assist the customer and the dealer in selecting the appropriate appliance

for the application. Consideration must be given to appliance location and configuration, environmental

conditions, insulation and air tightness of the structure.

Hearthstone Quality Home Heating Products, Inc ® Green Mountain Insert 70 (Model 8450)

43

THE WARRANTIES CONTAINED IN THIS DOCUMENT ARE EXCLUSIVE AND ARE GIVEN BY

HEARTHSTONE AND ACCEPTED BY THE ORIGINAL PURCHASER IN LIEU OF ALL OTHER EXPRESS

WARRANTIES AND ANY OBLIGATIONS, LIABILITIES, RIGHTS, CLAIMS, OR REMEDIES IN CONTRACT OR

TORT, WHETHER OR NOT ARISING FROM HEARTHSTONE’S NEGLIGENCE, ACTUAL OR IMPUTED. ALL

IMPLIED WARRANTIES, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

PARTICULAR PURPOSE, ARE GIVEN ONLY TO THE EXTENT REQUIRED BY FEDERAL OR STATE LAW.

EXCEPT AS OTHERWISE REQUIRED BY STATE LAW, UPON THE EXPIRATION OF THE EXPRESS

LIMITED WARRANTIES CONTAINED HEREIN, NO IMPLIED WARRANTIES, INCLUDING THE IMPLIED

WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, SHALL APPLY TO

THE SUBJECT APPLIANCE. SOME STATES DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED

WARRANTY LASTS, SO THE ABOVE LIMITATION MAY NOT APPLY TO YOU.

THE WARRANTIES CONTAINED IN THIS DOCUMENT EXTEND ONLY TO THE ORIGINAL PURCHASER OF

THE APPLIANCE WARRANTED HEREUNDER. THEY ARE NOT TRANSFERRABLE AND DO NOT EXTEND

TO ANY SUBSEQUENT OWNERS.

UNDER NO CIRCUMSTANCES SHALL HEARTHSTONE BE LIABLE TO THE ORIGINAL PURCHASER OR

ANY OTHER PERSON FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING BUT NOT

LIMITED TO DAMAGE TO PROPERTY OR PERSONAL INJURIES, WHETHER ARISING OUT OF LOSS OF

USE, BREACH OF WARRANTY, TORT, OR OTHERWISE, EVEN IF HEARTHSTONE HAS BEEN

APPRAISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE

EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE

LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU.

QUALIFYING FOR WARRANTY COVERAGE

To obtain performance of any obligation under this document, the Original Purchaser must, within the applicable

warranty time period, contact their original HearthStone dealer, or the current responsible local HearthStone

dealer, for instructions regarding the return of defective parts for repair, the return of the appliance for repair, or

to schedule a Dealer service call. The Original Purchaser should refer to the Dealer Network search engine

contained on HearthStone’s Web site (www.hearthstonestoves.com) if the original dealer is not available, to find

a HearthStone dealer nearest to the Original Purchaser’s location.

REMEDY

The remedy for any breach of the foregoing warranties will consist of repair or replacement, at HearthStone’s

option, of any covered defect in the appliance. When the Original Purchaser contacts a HearthStone Dealer, the

Dealer on behalf of HearthStone, as the case may be, will instruct the Original Purchaser to either return the

defective part, or the entire appliance (if requested), to the Dealer or HearthStone or allow a Dealer to make a

service call at the place where the appliance is located. HearthStone may require that a digital picture be

provided to support the claim. Notwithstanding any other provision of this document, the Original Purchaser

shall pay for any fees and service charges related to a Dealer’s service call or the shipping charges associated

with the return.

WARRANTY REGISTRATION

The Original Purchaser can complete their warranty registration on our website at www.hearthstonestoves.com,

or send a completed and signed Warranty Registration Form, which is enclosed in the appliance document

packet, to the following address:

HearthStone Quality Home Heating Products, Inc.

Warranty Department

317 Stafford Avenue

Morrisville, VT 05661

NOTE: SENDING IN THE SIGNED WARRANTY REGISTRATION FORM IS NOT REQUIRED AS A CONDITION OF

WARRANTY COVERAGE OR HEARTHSTONE’S PERFORMANCE.