HearthStone 8491 User manual

Hearthstone Quality Home Heating Products, Inc. ®
Clydesdale Model 8491
Manual: 6400-40462
R: 6 - 3/21/2013
Clydesdale
(Model 8491)
Non-Catalytic,
Wood Burning
Fireplace Insert
OWNER'S MANUAL
INSTALLATION & OPERATING
INSTRUCTIONS
Please read this entire owner’s manual before you install and use your new Clydesdale wood
burning fireplace insert. To reduce the risk of fire, follow the installation instructions. Failure
to follow these instructions may result in property damage, bodily injury, or even death.
SAVE THESE INSTRUCTIONS FOR FUTURE REFERENCE!
Contact Local Authorities Having Jurisdiction (Building Department or Fire Officials)
About Permits, Restrictions, and Installation Inspection Required in Your Area.

Hearthstone Clydesdale Fireplace Insert Model 8491
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Intentionally Blank

Hearthstone Clydesdale Fireplace Insert Model 8491
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Table of Contents
INTRODUCTION ....................................................................................................................................................4
CODES ...............................................................................................................................................................4
SAFETY INFORMATION..........................................................................................................................................5
PERIODIC CHECKLIST...........................................................................................................................................6
EMERGENCY PROCEDURES ..................................................................................................................................6
SPECIFICATIONS..................................................................................................................................................7
INSTALLATION .....................................................................................................................................................8
Unpacking......................................................................................................................................................................8
Packing List....................................................................................................................................................................8
Hearth Requirements & Floor Protection .......................................................................................................................9
Clearances to NFPA 211 Protected Surfaces................................................................................................................9
Clearance to combustibles.............................................................................................................................................9
Installing the Insert.......................................................................................................................................................10
Installing the surround..................................................................................................................................................14
Removing & Reversing the Door..................................................................................................................................14
Removing the Ash Lip Cover & Façade .......................................................................................................................15
Blower Power Cord Routing.........................................................................................................................................16
VENTING COMPONENTS &CONFIGURATION..........................................................................................................17
Installing a Venting System..........................................................................................................................................17
Connecting Your Wood Fireplace Insert ......................................................................................................................17
Connecting to a Prefabricated Metal Chimney.............................................................................................................17
Connection to a Masonry Chimney..............................................................................................................................18
OPERATION.......................................................................................................................................................21
Controls & Features.....................................................................................................................................................21
Operating the Blower ...................................................................................................................................................21
Choosing Firewood......................................................................................................................................................21
Wood Heat Value: Sorted By Btu Content ...................................................................................................................22
Building a Fire..............................................................................................................................................................23
Breaking in YourWood Fireplace Insert.......................................................................................................................23
Operating Your Insert Efficiently...................................................................................................................................24
Intermittent Operation ..................................................................................................................................................25
Building a Fire for Everyday Use..................................................................................................................................25
Disposal of Ashes ........................................................................................................................................................25
Over-Fire Caution.........................................................................................................................................................25
MAINTENANCE ..................................................................................................................................................26
Creosote Formation and Need for Removal.................................................................................................................26
Gaskets........................................................................................................................................................................26
Glass............................................................................................................................................................................26
Cast Iron.......................................................................................................................................................................27
Blower System.............................................................................................................................................................28
TROUBLESHOOTING...........................................................................................................................................29
Basic Heating Issues....................................................................................................................................................29
Draft Sampling Access Port.........................................................................................................................................29
Troubleshooting Guide.................................................................................................................................................30
REPLACEMENT PARTS &OPTIONAL ACCESSORIES...............................................................................................31
SAFETY LABEL..................................................................................................................................................32

Hearthstone Clydesdale Fireplace Insert Model 8491
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Introduction
Congratulations! You have just invested in a most
unique wood burning Fireplace Insert –the
Clydesdale Model 8491 is a clean burning EPA
certified, non-catalytic wood burning Fireplace
Insert. You can be proud to join the Hearthstone
family with our Premier Cast Iron Wood Burning
Fireplace Insert. The generous firebox depth and
width allows for loading of wood up to 22 inches
long!
Your purchase ensures years of clean, comfortable
heat with minimal maintenance. You will receive the
benefits of the most advanced technology in wood
burning without the cost and maintenance
requirements of a catalytic Fireplace Insert. The
Clydesdale blends modern technology with the
unique beauty and heating qualities of soapstone
(used as the firebox lining) and cast iron. Soapstone
is well known for its even heat production and long
heat-retaining ability. We trust that you will
appreciate the quality of our handcrafted product.
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 information that is useful to
you now, and in the years to come. So keep it handy
and refer to it as needed.
Use these instructions as well as national, state, and
local building codes to install your Fireplace Insert.
Ensure to maintain the designated stovepipe and
Fireplace Insert clearances to walls, ceilings, hearth,
and other combustible surfaces. This will help
reduce the risk of fire. Failure to follow these
instructions can result in property damage, bodily
injury, and even death.
Keep furniture, drapes, curtains, wood, paper, and
other combustibles far away from the Fireplace
Insert. Never install the Fireplace Insert in a location
where gasoline, kerosene, charcoal lighter fluid or
other flammable liquids are used or stored.
SAFETY NOTICE:
A HOUSE FIRE MAY RESULT IF THIS FIREPLACE
INSERT IS NOT INSTALLED PROPERLY. FOR YOUR
SAFETY, CAREFULLY FOLLOW THE INSTALLATION
INSTRUCTIONS. CONTACT LOCAL BUILDING OR
FIRE OFFICIALS ABOUT RESTRICTIONS AND
INSTALLATION INSPECTION IN YOUR AREA.
The performance of your Fireplace Insert depends
on many variables. Since all installations are
unique, the general information and operating
procedures presented here can only serve as useful
guidelines rather than hard and fast rules. Should
you have any questions, do not hesitate to contact
your dealer for additional information.
This Fireplace Insert is manufactured and warranted
by:
Hearthstone Quality Home Heating Products, Inc®
317 Stafford Ave.
Morrisville, VT. 05661
www.hearthstonestoves.com
Codes
When you install your Clydesdale wood Fireplace
Insert, it is imperative that you adhere to all local
codes, which can be obtained from either of the
following two National 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
http://www.nfpa.org

Hearthstone Clydesdale Fireplace Insert Model 8491
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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.
When using your Fireplace Insert:
Warn children and others unfamiliar with
woodstoves of the danger of touching hot,
radiating surfaces of your Fireplace Insert. For
your additional safety, obtain hearth and stove
guards through your local dealer.
Follow recommended break-in procedure as
outlined in this manual.
Burn natural wood only. Higher efficiencies and
lower emissions result when burning air-dried,
seasoned wood, as compared to green or
freshly cut wood.
Use caution when loading firewood into a hot
stove.
Inspect the stovepipe, chimney connector and
chimney, as recommended.
Follow these safety precautions:
Never modify this Fireplace Insert in any way,
especially the primary air control system.
Never burn kiln dried wood, painted or treated
wood, solvents, trash, plywood, colored or
glossy paper, plastic, artificial logs, cardboard,
coal, or driftwood. Especially, do not burn
coal in this Fireplace Insert.
Never use gasoline type fuel, kerosene,
charcoal lighter fluid, or other liquid fuels or solid
fire starters to start or invigorate the fire. These
fuels can possibly generate carbon monoxide,
which can sap the supply of oxygen. Keep all
such materials away from the Fireplace Insert.
Never use a log grate or other device to elevate
the fire.
Do Not allow logs to rest against or otherwise
come in contact with the glass when the door is
closed.
Do Not slam the door or use the door to force
wood in to the Fireplace Insert.
Never over-fire your Fireplace Insert
Never put articles of clothing or candles on a hot
Fireplace Insert.
Do Not connect the Fireplace Insert to a flue
that is serving another appliance.
Other safety guidelines
As a general rule, keep all combustible items
such as furniture, drapes, clothing, and other
items, at least 36" (0.92 m) from the Fireplace
Insert
Install a smoke detector, preferably in an area
away from your wood Fireplace Insert.
Install a CO detector as a rule. Wood burning
appliances can generate little CO, but oil and
gas burning appliances can produce huge
amounts if not operating properly.
Keep a fire extinguisher handy. We recommend
the type rated "A B C."
Dispose of ashes properly.
Keep children and pets away from the stove;
they could be burned by touching a hot stove.
Clean your chimney system as needed.

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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 begins to fill up).
At the Beginning of Every Other Month:
A visual inspection of the flue liner or chimney
for creosote is recommended depending upon
your use of the stove.
Check door seals using the "dollar bill test." -
When the fire is out and the insert is cool, shut
the door on a dollar bill. If the bill pulls out
without any resistance, then your insert’s door
isn't sealed properly. To tighten the seal, adjust
the latch spring tension or change the door
gasket if necessary.
At the End of Every Season:
Clean any chimney connector thoroughly.
Replace any pieces that show signs of rust or
deterioration.
Inspect and, if necessary, clean your chimney
(flue liner).
Thoroughly clean out the firebox of the Fireplace
Insert.
Inspect all door gasket material and replace if
worn, frayed, cracked or extremely hard.
Replace any badly cracked refractory soapstone
in the firebox.
Clean dust away from the ash lip assembly and
grills.
Remove the Ash Lip Cover and inspect the
blower assembly - clean if necessary.
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 two steps.
2. Close the primary air control.
3. Keep the Fireplace Insert door closed!
WARNING: DO NOT ATTEMPT TO PUT OUT A
STOVEPIPE OR CHIMNEY FIRE BY THROWING
WATER ONTO THE STOVE, STOVEPIPE, OR
CHIMNEY. THE EXTREMELY HIGH
TEMPERATURE ASSOCIATED WITH SUCH FIRES
CAN CAUSE INSTANTANEOUS STEAM AND
SERIOUS BODILY HARM.
Once the chimney fire has expired, leave the primary
air control closed and let the fire in the Fireplace
Insert die out completely. DO NOT burn the
Fireplace Insert again until the Fireplace Insert,
connector pipe, liner, and chimney are all thoroughly
inspected for any sign of damage. You must correct
any damage before using your Fireplace Insert
again.
To remove the Clydesdale for inspection purposes,
disconnect the venting from inside the firebox.
Carefully remove the surround from the insert, and
slide the insert away from the fireplace.

Hearthstone Clydesdale Fireplace Insert Model 8491
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Specifications
Maximum Heat Output: 60,000 BTU per hour of
cordwood (based on independent laboratory test
results).
Size of Heated Area: Up to 2,000 square feet.
Firebox Capacity: 2.4 cubic feet or 48 pounds of
wood (The amount and weight of wood contained per
cubic foot of firebox volume can vary from 15 to 36
lbs. per cubic foot depending on type of wood,
moisture content, packing density and other factors.
As a constant for comparison and test purposes, we
are assuming 20 lbs. of seasoned hardwood per
cubic foot of firebox volume).
Maximum Log Length: 22” (55.88 cm)
Height: 23.12" (58.72 cm)
Width: 31.62” (80.31 cm)
Depth: 24.63” (62.56 cm)
Front Door Size: 22" wide x 11.5" high
(55.88 x 29.21 cm)
Stovepipe Size: 6" (152 mm) diameter
Metal Chimney: 6" (152 mm) inside diameter
Masonry Chimney: 6” (15.2cm) inside diameter
(round flue)
8” x 8” (20 x 20cm) (square
flue)
Flue Exit: Top exit only
Actual Weight: 550 pounds
Castings Finish: Painted Matte; and Porcelain
Enamel
Figure 1 –Clydesdale Dimensions

Hearthstone Clydesdale Fireplace Insert Model 8491
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Installation
Unpacking
Hearthstone packages your Clydesdale Fireplace
Insert with the greatest care so that it ships safely.
Under certain circumstances, however, damage can
still occur during transit and handling. When you
receive your Fireplace Insert, unpack it carefully,
inspecting it, and all parts for damage. Also, ensure
that all parts are included. If any parts are damaged
or missing, please contact your dealer immediately.
Packing List
1- Clydesdale 8491 Fireplace Insert
1- Façade and Ash Lip w/ blower (in place on insert)
1- Façade Top Grill (in place on insert)
1- Surround Kit Box (ships on top of insert)
In Firebox:
1- Box, Refractory Stone Kit
1- Bag, Door Handle Kit
1- Envelope, Owner’s Manual Packet
1- Pouch, Touch-up Paint (Enamel only)
Pre-Installation Prep
When installing this unit in a fireplace, you must
attach the provided metal label (3300-625) to the
fireplace prior to installing the insert (see illustration
on page 18).
WITH ALL CHIMNEYS, A POSITIVE CONNECTION
MUST BE MADE BETWEEN THE FIREPLACE
INSERT’S FLUE COLLAR AND THE CHIMNEY (see
page 17).
Ensure that the Fireplace Insert will have enough
clearance to combustible materials in the vicinity.
These combustibles can include walls, floor, ceiling,
fireplace mantle, and chimney decor. You must
carefully consider the clearances to all of these
combustibles before actually connecting your
Fireplace Insert.
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
Figure 2 –Minimum Fireplace Dimensions

Hearthstone Clydesdale Fireplace Insert Model 8491
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Hearth Requirements & Floor
Protection
Combustible flooring must be protected with a
covering of noncombustible material (slate, marble
tiles, other noncombustible material can be used for
this purpose). The floor protection must extend
beyond the body of the Fireplace Insert at the
minimum as follows and have a minimum “R-Value”
of 1.0.
Figure 3 –Hearth Requirements
Noncombustible Material
Thickness
R-value
Gypsum or plaster board1
1/2
0.45
Wallboard,Wonderboard, or
Durock1
1/2
0.20
Ceramic board (Fiberfrax or
Micor)1
1/2
1.10
Nominal solid clay brick1
1
0.20
Ceramic wall or floor tile1
1/4
0.01
Mineral wool insulation2
1
3.12
Cement mortar2
1
0.20
Horizontal still air2*
1/8
0.92
Floor protectors come with various types of
specifications. To convert a floor protector’s
specification to an R-value, do one of the following:
1. If the R-value is given, use that value - no
conversion is needed.
2. If a K-factor is given with a required thickness (T)
in inches, use this formula: R-value = 1/K x T
3. If a C-factor is given, use the formula: R-value =
1/C
To determine the R-value of the proposed alternate
floor protector:
1Check manufacturer’s specifications
2According to ASHRAE Handbook of Fundamentals 1977
1. Use either the K-factor or the C-factor formula
explained above to convert specifications not
expressed as R-values.
2. For multiple layers of floor protectors, simply add
the R-values of each layer to determine the
overall R-value of the layers.
If the overall R-value of your setup is greater than the
R-value of the specified floor protector, then your
setup is acceptable.
Clearances to NFPA 211 Protected
Surfaces
You can reduce the clearances to combustible
surfaces by using any National Fire Protection
Agency (NFPA) approved wall protection system.
Refer to NFPA 211 for specific and complete details:
National Fire Protection Agency
Battery March Park
Quincy, MA 02269
1-800-344-3555
1-617-770-3000
www.nfpa.org
Clearance to combustibles
Figure 4 –clearances to combustibles
A- Side wall = 12”
B- Mantle and top trim = 27” *
B- Mantle/ with mantle shield kit = 11” *
C- Trim = 9”
*Measured from top of sheet metal shroud

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Installing the Insert
Step One: Remove the contents of the firebox. This
will include the owner’s manual packet, a box of
soapstone refractory bricks, the handle knob
assembly, and a pouch containing enamel touch-up
(if applicable).
Step Two: Remove the Clydesdale from the pallet
(see Photo 1).
Locate the three mounting clips attached to the
leveling bolts (two in the front and one in the back)
that secure the insert to the shipping pallet.
1. Using a 1/2”wrench, remove the rear lag
screw and mounting clip.
2. Check the front clips –if there is sufficient
clearance above the lag screws to clear the
facade, remove them.
3. Otherwise, if the lag screw is close to and
under the façade (see photo 1), carefully
loosen the front clip lag screws about one
turn. Take care to not damage the finish on
the façade.
4. Slide the insert backwards about one inch to
disengage the front clips.
5. Once all the clips are disengaged, turn the
rear leveling bolt upward (tighten) to ease
insert installation into the fireplace.
The Insert ships with the Façade and ash lip cover
installed. You should not need to remove these in a
typical installation.
Photo 1 –Pallet Mounting Clip Detail (Right Front
Shown - Façade Installed)
Step Three: Install the wooden knob onto the latch
handle. The knob, and bolt are located in a plastic
bag removed from the firebox in step one. Push the
bolt through the knob. Turn the bolt onto the latch
handle and tighten with a hex wrench. Handle is
shown installed correctly in photo 2.
Photo 2 –Door Handle & Latch Detail
Step Four: Measure the opening of the fireplace.
When measuring the fireplace cavity, you will need to
determine the following:
1. Will the flue collar be installed in the forward
or aft position? The depth of the firebox will
determine the location of the flue collar.
NOTE: the collar is installed at the factory in
the aft position to accommodate the most
common type of install that requires use of
an elbow or flex connector for attachment to
the chimney liner. To change the collar to
the forward position for a shallow fireplace,
follow the instructions in step five. Proceed
to the next step if the aft position is correct
for your installation.
2. Note: With the collar is in the aft position - to
properly attach the liner or connector to the
flue collar using all three screws, you must
remove the baffle/plenum and drop the flue
collar into the firebox for attachment of the
flue liner. If the baffle/plenum and flue collar
do not need to be removed, you can skip to
step 7.
Step Five: Change the position of the flue collar if
necessary. To remove the flue collar, reach in
through the flue collar and locate the four bolts
threaded down through the insert top on the corners
of the flue collar. Remove the nuts with a 7/16”
wrench. Lower, and turn the collar 180 degrees to
the forward position. Fit the four holes on the collar
over the four bolts. Fasten the nuts back onto the
bolts and tighten them with the 7/16” wrench. Now

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place the insert into the fireplace opening and
connect to the flue liner (meeting UL 1777).
Photo 3 –Collar Mounting Detail (Inside Firebox)
Photo 4 –Air Shroud Installed (default)
Photo 5 - Collar in Default 30º Aft Position (air
shroud removed for clarity)
Photo 6 –Collar in Forward (90º Position)
NOTE: In order to connect the liner to the flue
collar properly with three screws when the flue
collar is in the aft (default) position, you must
remove the baffle/plenum and drop the collar into
the firebox. Removing the baffle will also allow
you to connect the flue liner to the flue collar in
the forward position if space above the insert
installed in the fireplace is limited.
Draft Sampling
Port

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Step Six: Remove the baffle/plenum.
Photo 7 –Stone Clip Detail
NOTE: Before the baffle can be removed, the 3
stone retaining clips (one in the rear and one on
each side) must be removed from the firebox.
Remove the clips by removing the fasteners that
hold them to the firebox.
1. To remove the baffle / secondary air plenum,
loosen the two socket head machine screws that
hold it in place with a 5/32” hex wrench (see
photo below). Once these screws are loose, lift
the baffle assembly off the screws and maneuver
it carefully out of the firebox.
Photo 8 –Plenum Fastener Detail
The removable plenum/baffle assembly inside the
Clydesdale firebox. (Shown looking straight into the
firebox.)
NOTE: If access to the top of the insert is
restricted when installed, you will want to loosely
attach the mounting bracket for the surround
now. For installation details see the instructions
provided with the surround.
2. With the baffle/plenum out of the firebox, remove
the flue collar as described in step five. Place the
flue collar in the firebox and insert the Clydesdale
into the fireplace opening. Drop the flue liner
(meeting UL 1777) into the firebox through the
flue collar opening. Attach the flue liner, or
connector to the collar, push the collar and flue
liner up to the top of the firebox, ensure the collar
slips onto the four bolts, and secure it by turning
the nuts back onto the bolts and tighten with a
7/16” wrench.
Place the baffle / secondary air assembly back into
the firebox and re-install.
CAUTION: THE BAFFLE MATERIAL IS A HIGH
TEMPERATURE CERAMIC. IT WILL LAST FOR
MANY YEARS UNDER NORMAL USE; HOWEVER,
IT IS EASILY DAMAGED BY IMPACT OR FORCE.
APPLY PRESSURE TO THE STAINLESS STEEL
AIR TUBES AND CAST IRON ONLY!
a. Place the baffle inside the stove with the ceramic
board facing up, and the stainless steel shelf tabs
forward.
b. Lift the baffle and slide the rear baffle sleeves
fully into the slots on the rear of the unit. The
slots on the baffle will drop back onto the
threaded rods in the back of the firebox
c. Gently lower the front of the baffle until the shelf
tabs are resting on the sidewall.
d. To verify that the baffle is in the correct position,
gently tug down on the front of the baffle. If it
does not move –placement is correct. Tighten
the machine screws loosened in step one.
Photo 9 –Baffle/Plenum Shelf Tab Detail
Shelf Tab
Ceramic Baffle
Stone Clips.

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Step Seven: With the unit in the desired position
within the fireplace, level the unit using a box end
wrench on the square portion of the left and right
leveling bolts (if façade is installed). Use a 9/16”
socket wrench on the Stover nut to adjust the rear
leveling bolt (see photos 10 through 12).
Photo 10 –Leveling Bolt Detail (Right Front Shown
with Façade removed & Stover lock nut installed)
Photo 11 –Rear Leveling Bolt Detail (With Stover
lock nut installed - accessed in Firebox)
Photo 12 –Rear Leveling Bolt (Rear View)
Step Eight: Install the soapstone refractory pieces in
the firebox (see photos 13 through 15).
The Clydesdale refractory stone set includes the
following stones:
9 ea: 4-1/2” x 9” (A)
1 ea: 4-1/2” X 4-1/2” (B)
2 ea: 4-1/2” X 12” Angled Cut (C)
2 ea: 4-1/2” x 11-1/4” Angled Cut (D)
Photo 13 –Firebox Floor Stones
Photo 14 –Install & Secure Firebox Rear Stones
Photo 15 –Left and Right Side Stones
PHOTO #13
Secure the rear stone with
the rear stone-retaining
clip. Slide retaining clip
down onto bolt heads and
tighten.
PHOTO #12
Set three stones vertically
against the back of the
firebox
A
A
A
A
A
A
B
A
A
C
D
A

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Installing the surround
Step Nine: Remove the surround components from
the large cardboard box that accompanied the
Clydesdale Insert. Included are the surround panels,
assembly hardware, and surround mounting bracket.
Refer to the instructions included with the surround
for complete assembly and installation.
Read this Owner’s Manual for all other installation
and operational requirements.
Removing & Reversing the Door
To reverse the door to open from the right, first cover
the ash lip cover with cardboard or a towel (to avoid
scratching it), then remove the door.
1. Open and support the door, then remove the machine
screw securing the upper inner hinge. Lift the door off
the lower, inner hinge section.
1.
Photo 16 –Upper Hinge Mounting Detail
Photo 17 –Lower Hinge Mounting Detail
2. Remove the lower hinge section from the insert.
3. Remove, and set aside the two hinge pins and any
spacer washers.
Photo 18 - Reversible Door Catch
Photo 19 –Reversible Door Stop
4. Use a hex wrench to remove the door catch and the
screws (and the door stop if present) on the right side.
5. Reattach the door catch on the opposite side of the
front, using the same screws. Reattach the screws
(and door stop if present) on the left where the catch
was.
6. Remove the two Phillips head screws where the
hinges will go on the left side –install them on the right
side.
7. Rotate both inner hinge sections 180 degrees and
mount the lower hinge’s inner section on the left side
of the insert.
8. Rotate the door 180 degrees –you do not have to
remove or adjust the handle.
9. Insert the pin in the lower hinge’s outer section.
10. Insert the hinge pin in the upper hinge’s inner section
and place it on the upper outer hinge section still
attached to the door, reinstall any spacers.
11. Position the door so it is open about 80 degrees and
place it on the lower inner hinge section.
12. Attach the upper inner hinge section to the insert.
13. Tap the pins down to seat them if necessary.
14. Close the door and check its alignment –ensure it is
square in the opening, and that it does not drag on the
ash lip cover. Adjust the hinges/spacers if needed.
15. Check the gasket seal using the dollar bill test. Close
the door on a dollar bill –if the bill pulls out without any
resistance at any point; this is where it will leak, adjust
the door accordingly.
Inner Hinge
Section
Outer Hinge
Section

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Removing the Ash Lip Cover &
Façade
In some instances, it may become necessary to
remove the Façade or Ash Lip Cover. To remove the
Façade, you must first remove the Ash Lip Cover. To
service the blower, you must also remove the Ash Lip
Cover.
1. To remove the Ash Lip Cover, loosen the two hex
socket head set screws securing the ash lip cover as
shown in photo 20. In order to lift the ash lip cover, you
must loosen the set screws enough to clear the
mounting clips (see photo 21).
Photo 20 –Ash Lip Cover Detail
Photo 21 –Ash Lip Cover Mounting Clip Detail
2. To remove the Façade, first remove the top grill (see
photo 22). On brown enamel Clydesdales, carefully lift
the grill straight up to avoid scratching or chipping the
façade’s finish.
Photo 22 –Top Grill
Photo 23 –Top Grill Adjustment Point Detail
3. The Top Grill on brown enamel finish Clydesdales
uses three adjustment points to keep the grill from
resting on the façade’s enamel surface. The draft port
plug (see photo 32), and two setscrews (see photo
above) are adjusted at the factory, but may need
further adjustment after installation or maintenance.
4. Lift the Façade up slightly and tilt it towards you so the
mounting clips clear the lip on the stove body (see
photo 24). Carefully move the Façade away from the
insert and set aside.
Photo 24 –Façade Clip Detail (rear view)
5. When ready, reinstall the Façade, Top Grill, and Ash
Lip Cover.
Note: The façade is correctly mounted when the clips
are positioned as shown in photo 24. Do not remount
the façade and place the mounting clip behind the
second inner cast lip shown above.
Ash Lip Cover
Mounting Clip (2)
Façade Clip (2)
Ash Lip
Cover
Set Screw (2)
Top Grill
Leave exposed
Setscrews
Rear Notch

Hearthstone Clydesdale Fireplace Insert Model 8491
Page 16 of 33
Blower Power Cord Routing
The Clydesdale 8491 ships from the factory with the
blower system’s power cord routed on the left side of
the insert as you face it. If your installation requires
the cord on the right side, you must remove the
façade and disassemble the ash lip assembly to
access the wire clips to change the position of the
power cord.
1. Loosen Set Screw and remove Ash Lip Cover.
Remove the Façade as described on page 15.
Photo 25 –Set Screw Detail
2. Remove screw and step bushing securing the air
control to the bracket.
Photo 26 –Air Control Mounting Detail
3. Use a 1/2” socket, or wrench and remove the 4
bolts and washers securing the Ash Lip
Assembly to the body of the insert. There is no
need to disconnect any wires.
Photo 27 –Ash Lip Assembly Fastener Detail
4. Use a Phillips head screwdriver to remove the
screws securing the wire loops on the left and
transfer everything to the right side ensuring you
place the loops in the equivalent locations
(arrows). A wire loop must be placed on the
screw closest to the corner to ensure the cord
does not rub on the blower housing. Do not
disconnect any wiring –there is more than
sufficient length to route the cord to the right over
the top of the blower speed control.
Photo 28 –Wire Loop Mounting Detail
5. Re-attach the ash lip assembly to the front of the
insert. Ensure the cord is not touching the blower
housing and is routed through the space above
the mounting flange. Ensure the cord is not
pinched in any way. Re-attach the screw and
step bushing securing the air control to the
bracket. Ensure the air control moves freely. Re-
install the façade and then the ash lip cover.
Photo 29 –Correctly Routed Cord Detail

Hearthstone Clydesdale Fireplace Insert Model 8491
Page 17 of 33
Venting Components & Configuration
Installing a Venting System
DO NOT CONNECT THIS UNIT TO ANY AIR
DISTRIBUTION DUCT OR SYSTEM
Secure all joints, including attaching the flue liner
to the Fireplace Insert's flue collar, with three
sheet metal screws. Install #10 x 1/2" (3 mm x 13
mm) sheet metal screws into the holes pre-drilled in
the flue collar. Eliminating the screws can cause
joints to separate from the vibrations that result from
a creosote chimney fire.
Remember, the NFPA has recommended minimum
clearances for chimney connectors to combustibles
such as walls and ceilings. Once the Fireplace Insert
is installed at safe distances from these combustible
surfaces, it is important to maintain these connector
clearances for the remainder of the installation.
Connecting Your Wood Fireplace
Insert
You can connect your Clydesdale to a prefabricated
metal chimney or a masonry chimney. See Figure 5
for an example to aid in connections.
With all chimneys, a positive connection must
be made between the fireplace insert’s flue
collar and the chimney.
In an existing Masonry Chimney, use one of the
approved following methods:
In the U.S:
1. Connect the insert to a listed 6” stainless steel
flexible connector that connects to a listed 6”
stainless steel liner extending the full length of
the chimney.
A 22 ga. or greater Blue Steel 6”
connector is also acceptable to
attach to the flue liner.
2. Connect the insert to a listed 6” stainless steel
flexible connector that extends beyond the
fireplace’s damper into an approved flue tile liner.
3. In all cases, a sealed block off plate, or a plug of
other noncombustible material such as unfaced
fiberglass insulation, must be installed at the
damper area of the existing fireplace to seal the
chimney from the room air.
In Canada:
4. The fireplace insert must be installed with a
continuous chimney liner with a minimum
diameter of 6” extending from the fireplace insert
to the top of the chimney. The chimney liner must
conform to the class 3 requirements of chimney
liner standards can/ulc-s635 or can/ulc-s640.
Do not use aluminum or galvanized steel pipe
as a connector or chimney liner. These
materials are not suitable for solid fuel
burning applications.
Connecting to a Prefabricated
Metal Chimney
You can install the Clydesdale in masonry or zero
clearance fireplaces. Before installing the stove in a
factory-built fireplace, the fireplace must have the
following characteristics:
1) Listed per UL 127 or ULC S610.
2) Include a full height listed chimney liner meeting
type HT requirements (2100° Fahrenheit) per UL
1777 (United States) or ULC S635 (Canada)
standards.
3) The means to prevent room air passage to the
chimney cavity of the fireplace.
4) Does not disturb the airflow in or within the
fireplace when installed (louvers, or cooling air
inlet or outlet ports must not be blocked).
5) Not be altered in any way, except for the
following:
a) External trim pieces which do not affect the
operation of the fireplace can be removed,
providing they are stored on or within the
fireplace for re-assembly if the insert is
removed.
b) The chimney damper can be removed to
install the chimney liner.
6) Must not have blocked circulating chambers (if
available).
7) The means for removing the insert to clean the
chimney flue.
8) Have a permanent metal warning label (provided
with the Clydesdale—see following illustration)
attached to the fireplace by riveting it to the
outside wall, stating that the fireplace must be
restored to its original condition for safe use
without the insert.

Hearthstone Clydesdale Fireplace Insert Model 8491
Page 18 of 33
Remember, you must adhere to all previously
described floor protection requirements when
installing into a zero clearance fireplace.
WARNING: DO NOT CONNECT THE FIREPLACE
INSERT TO A CHIMNEY FLUE SERVING ANOTHER
APPLIANCE.
Ensure the size of the chimney’s flue is appropriate
for the Clydesdale. The Clydesdale requires a 6"
(152 mm) inside diameter flue for new installations.
A 6” diameter flue provides adequate draft and
performance. You can use an 8" (203 mm) diameter
existing flue with a reducer. An oversized flue
contributes to creosote accumulation. (In this case,
bigger is NOT better.)
There are two ways to install a prefabricated metal
chimney:
An interior installation where the chimney passes
inside the residence through the ceiling and roof.
An exterior installation where the chimney passes
through the wall behind the Fireplace Insert then
up the outside of the residence.
Whenever possible, choose an interior chimney. An
interior chimney heats quickly and retains its heat;
thus promotes a better draft and discourages the
formation of creosote. An exterior chimney does not
benefit from the surrounding warmth of the building,
so it typically operates at lower flue temperatures
than an interior chimney. An exterior chimney’s draft
is not as strong and may experience increased
creosote accumulation.
REMOVE THE DAMPER OR LOCK IT OPEN.
Connection to a Masonry Chimney
Hire a professional to examine the masonry chimney
for cracks, loose mortar, and other signs of
deterioration and blockage before connection. If the
chimney needs repairs, complete them before
installing and using your Fireplace Insert. Do not
install your Fireplace Insert until the chimney is safe
for use.
Ensure the chimney’s cleanout is complete and
working properly. To avoid a loss of draft, the
cleanout must close off completely.
Ensure the size of the chimney’s flue is appropriate
for this Fireplace Insert and that it is not too large.
Use a masonry chimney with a maximum 8" x 8" (203
mm x 203 mm) tile size for best results. An oversized
flue will contribute to the accumulation of creosote.
Use the following checklist to ensure that your
masonry chimney meets these minimum
requirements:
Chimney wall construction:
A brick, modular block, rubble or stone wall at
least 4" (102 mm) thick.
Flue liner:
Minimum ceramic flue liner thickness of 5/8" (16
mm). Installed with refractory mortar and with at
least 1" (25 mm) air space.
An equivalent listed chimney flue liner system
meeting type HT requirements or other approved
material.
Interior chimney requirements:
At least 2" (51 mm) clearance to combustible
structure
Fire stops installed at the spaces where the
chimney passes through floors and/or ceiling.
Insulation must be 2" (51 mm) from the chimney.
Exterior chimney requirements:
At least 1" (25 mm) clearance to combustible
structure.
Chimney height requirements: (See page 20)
At least 3 feet (0.9 m) higher than the highest
part of the roof opening through which it passes.
At least 2 feet (0.6 m) higher than any part of the
roof within 10 feet (3 m) measured horizontally
from the top of the chimney. This Fireplace
Insert requires a minimum chimney height of 13
feet (4 m). The maximum recommended
chimney height is 30 feet (9m).
IMPORTANT: You must seal the damper area
around the chimney liner to prevent room air
from entering the chimney cavity of the
fireplace.
WARNING: DO NOT REMOVE BRICKS OR
MORTAR FROM THE EXISTING FIREPLACE!
(Exception) Removal of masonry or steel (including
the damper plate) from the smoke shelf and adjacent
damper frame if necessary to accommodate a
chimney liner, provided their removal will not weaken
the structure of the fireplace and chimney, and will
not reduce protection for clearance to combustible
materials to less then required by the National
Building Code.

Hearthstone Clydesdale Fireplace Insert Model 8491
Page 19 of 33
Figure 5 –Connecting to a masonry chimney

Hearthstone Clydesdale Fireplace Insert Model 8491
Page 20 of 33
Figure 6 –The 2 / 10 / 3 Chimney Exit Clearance Rule
Figure 7 –Minimum Chimney Height Is 3’ Even At the Ridge