Heatilator ST42A User manual

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 1
Owner’s Manual
Installation and Operation
Model:
ST42A
See-Through
Woodburning Fireplace
DO NOT DISCARD THIS MANUAL
CAUTION
• Important operating
and maintenance
instructions included.
• Leave this manual with
party responsible for
use and operation.
• Read, understand
and follow these
instructions for safe
installation and
operation.
DO NOT
DISCARD
Installation and service of this fireplace should
be performed by qualified personnel. Hearth
& Home Technologies suggests NFI certified
or factory-trained professionals, or technicians
supervised by an NFI certified
professional.
If the information in these instruc-
tions is not followed exactly, a
fire may result causing property
damage, personal injury, or death.
• Do not store or use gasoline or other flam-
mable vapors and liquids in the vicinity of
this or any other appliance.
• Do not overfire. Overfiring will void your
warranty.
• Comply with all minimum clearances to
combustibles as specified. Failure to
comply may cause house fire.
WARNING
Fire Risk
• For use with solid wood fuel or decorative
gas appliance only.
• Do not install unvented gas logs.
WARNING
WARNING
Hot glass will cause burns.
• Do not touch glass until it is cooled
• NEVER allow children to touch glass
• Keep children away
• CAREFULLY SUPERVISE children in same room
as fireplace.
• Alert children and adults to hazards of high
temperatures.
High temperatures may ignite clothing or other
flammable materials.
• Keep clothing, furniture, draperies and other
flammable materials away.
HOT SURFACES!
Glass and other surfaces are
hot during operation AND
cool down.
¨

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
2
Read this manual before installing or operating this fireplace.
Please retain this owner’s manual for future reference.
Congratulations on selecting a Heatilator wood burning fire-
place. The Heatilator fireplace you have selected is designed
to provide the utmost in safety, reliability and efficiency.
As the owner of a new fireplace, you’ll want to read and care-
fully follow all of the instructions contained in this owner’s
manual. Pay special attention to all cautions and warnings.
This owner’s manual should be retained for future reference.
We suggest you keep it with your other important documents
and product manuals.
The information contained in this owner’s manual unless noted
otherwise, applies to all models and gas control systems.
Your new Heatilator wood burning fireplace will give you years
of durable use and trouble-free enjoyment. Welcome to the
Heatilator family of fireplace products!
Homeowner Reference Information
Model Name: Date purchased/installed:
Serial Number: Location on fireplace:
Dealership purchased from: Dealer phone:
Notes:
We recommend that you record the following pertinent
information about your fireplace:
Listing Label Information/Location
The model information regarding your specific fireplace can be found on the rating plate located on the smoke shield of the
fireplace.
Congratulations!
FIREPLACE NO.
MODEL NO.
MODEL NO.
MFG. DATE
WARNING: RISK OF
FIRE DAMAGE. REPLACE
GRATE WITH HEARTH & HOME
TECHNOLOGIES INC.
FIRECHAMBER INTENDED FOR USE WITH HEARTH & HOME TECHNOLOGIES INC. LISTED FIREPLACE PARTS. SEE INSTALLATION AND
OPERATING INSTRUCTIONS FOR THIS MODEL. ONLY HEARTH & HOME TECHNOLOGIES INC. GLASS DOOR KITS CAN BE INSTALLED ON THIS UNIT.
FIREPLACE ALSO FOR USE
IN MANUFACTURED HOMES
YES NO
CLEARANCE TO
COMBUSTIBLES:
CHIMNEY
2 IN. MIN.
FIREBOX
IN.
MIN.
FAN KIT
MODEL NO.
&RATED AT
115 VOLTS, 50/60 Hz., AMP.
DO NOT OVERFIRE. USE ONLY: SOLID WOOD FUEL OR
LISTED DECORATIVE GAS APPLIANCE. DO NOT USE A
FIREPLACE INSERT OR OTHER PRODUCTS NOT
SPECIFIED FOR USE WITH THIS PRODUCT. IF DOORS
ARE USED OPERATE FIREPLACE WITH DOORS FULLY
OPEN OR CLOSED ONLY. WHEN BURNING A
DECORATIVE GAS APPLIANCE IN THE FIREPLACE,
ADJUST DAMPER TO THE FULLY OPEN POSITION.
WARNING! THIS FIREPLACE HAS NOT BEEN TESTED WITH AN UNVENTED
GAS LOG SET. TO REDUCE THE RISK OF FIRE OR INJURY, DO NOT
INSTALL AN UNVENTED GAS LOG SET INTO FIREPLACE.
WARNING! THIS APPLIANCE IS NOT FOR USE AS COOKING EQUIPMENT.
IF INSTALLATION OR OPERATING INSTRUCTIONS ARE MISSING
CONTACT: HEARTH & HOME TECHNOLOGIES INC.,
1915 W. SAUNDERS ST., MT. PLEASANT, IA 52641.
Grate Fireplace
Model
Serial
Number

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 3
Table of Contents
1 Listing and Code Approvals
A. Appliance Certification. . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Getting Started
A. Design and Installation Considerations . . . . . . . . . . . . 5
B. Negative Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
C. Typical Fireplace System. . . . . . . . . . . . . . . . . . . . . . . 7
D. Tools and Supplies Needed. . . . . . . . . . . . . . . . . . . . . 8
E. Inspect Fireplace and Components. . . . . . . . . . . . . . . 8
3 Framing and Clearances
A. Selecting Fireplace Location . . . . . . . . . . . . . . . . . . . . 9
B. Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
C. Sidewalls/Surrounds . . . . . . . . . . . . . . . . . . . . . . . . . 11
D. Frame the Fireplace . . . . . . . . . . . . . . . . . . . . . . . . . 11
E. Construct the Chase . . . . . . . . . . . . . . . . . . . . . . . . . 12
F. Chimney Requirements. . . . . . . . . . . . . . . . . . . . . . . 12
4 Installation of Fireplace
A. Install the Outside Air Kit . . . . . . . . . . . . . . . . . . . . . . 13
B. Secure the Fireplace . . . . . . . . . . . . . . . . . . . . . . . . . 15
5 Chimney Assembly
A. Chimney Requirements. . . . . . . . . . . . . . . . . . . . . . . 17
B. Using Offsets/Returns . . . . . . . . . . . . . . . . . . . . . . . . 18
C. Assemble the Chimney Sections. . . . . . . . . . . . . . . . 19
D. Install the Ceiling firestops. . . . . . . . . . . . . . . . . . . . . 19
E. Install the Attic Insulation Shield . . . . . . . . . . . . . . . . 20
F. Double-check the Chimney Assembly. . . . . . . . . . . . 21
G. Secure the Chimney . . . . . . . . . . . . . . . . . . . . . . . . . 21
6 Complete the Enclosure
A. Chimney Termination. . . . . . . . . . . . . . . . . . . . . . . . . 22
B. Chase Top . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
C. Install the Termination Cap . . . . . . . . . . . . . . . . . . . . 24
7 Accessories
A. Gas Log/Lighter Provisions . . . . . . . . . . . . . . . . . . . . 26
8 Finishing
A. Hearth Extension. . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
B. Finishing Material . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
C. Mantel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
D. Sidewalls/Surrounds . . . . . . . . . . . . . . . . . . . . . . . . . 29
E. Glass Doors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
9 Operating Instructions
A. General Information. . . . . . . . . . . . . . . . . . . . . . . . . . 30
B. Outside Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
C. Clear Space Near the Fireplace . . . . . . . . . . . . . . . . 31
D. Flue Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
E. Firescreen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
F. Glass Doors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
G. Grate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
H. Wood Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
I. Starting a Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
10 Troubleshooting
A. Understanding Vent Problems. . . . . . . . . . . . . . . . . . 34
B. Diagnostics and Problem Solving . . . . . . . . . . . . . . . 35
11 Maintenance and Servicing the Fireplace
A. Disposal of Ashes . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
B. Chimney Inspection/Cleaning . . . . . . . . . . . . . . . . . . 37
C. Firebox Refractory. . . . . . . . . . . . . . . . . . . . . . . . . . . 37
D. Maintenance Task List . . . . . . . . . . . . . . . . . . . . . . . . 38
E. Chimney Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
12 Reference Materials
A. Fireplace Dimensions . . . . . . . . . . . . . . . . . . . . . . . . 39
B. Fireplace Components . . . . . . . . . . . . . . . . . . . . . . . 40
C. Chimney Components. . . . . . . . . . . . . . . . . . . . . . . . 41
D. Service Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
E. Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
F. Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Note: An arrow (¨) found in the text signifies change in content.

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
4
1
1 Listing and Code Approvals
A. Appliance Certification
This fireplace system has been tested and listed in accor-
dance with UL 127 and ULC-S610 standards by Underwrit-
ers Laboratories Inc. for installation and operation in the
United States and Canada.
This fireplace has been tested and listed for use with the op-
tional components specified in this manual. These optional
components may be purchased separately and installed at
a later date. Installation of an outside air kit will require sig-
nificant reconstruction and is best if installed at the time of
fireplace installation.
Heatilator is a registered trademark of Hearth & Home Tech-
nologies Inc.
Not intended for use as a primary heat source.
This fireplace is tested and approved as a decorative fire-
place. It should not be factored as a primary heat source
in residential heating calculations.
Improper installation, adjustment, alteration, service
or maintenance can cause injury or property damage.
Refer to the owner’s information manual provided with
this fireplace. For assistance or additional information
consult a qualified installer, service agency or your
dealer.
WARNING
Fire Risk
• Do not install or operate damaged fireplace.
• Do not modify fireplace.
• Installation other than as instructed by Hearth & Home
Technologies Inc. is strictly prohibited.
• Do not operate the fireplace without fully assembling
all components.
• Do not overfire.
•Do not install an unvented gas log set. This fireplace
has not been tested for use with unvented gas log
sets.
• Installation and/or use of any component part not
approved by Hearth & Home Technologies.
Hearth & Home Technologies disclaims any responsibility
for, and the warranty and agency listing will be voided by
the above actions.
WARNING

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 5
2
2 Getting Started
A. Design and Installation Considerations
Draft is the pressure difference needed to vent fireplaces
successfully. Considerations for successful draft include:
• Preventing negative pressure
• Location of fireplace and chimney
B. Negative Pressure
Negative pressure results from the imbalance of air avail-
able for the fireplace to operate properly. Causes for this
imbalance include:
• Exhaust fans (kitchen, bath, etc.).
• Range hoods.
• Combustion air requirements for furnaces, water heaters
and other combustion appliances.
• Clothes dryers.
• Location of return-air vents to furnace or air
conditioning.
• Imbalances of the HVAC air handling system.
• Upper level air leaks: recessed lighting, attic hatch
opening, duct leaks.
To minimize the effects of negative air pressure, the follow-
ing must be considered:
• Install the outside air kit. Install the intake on the side of
the house towards prevailing winds during the heating
season.
• Ensure adequate outdoor air is supplied for combustion
appliances and exhaust equipment.
• Ensure furnace and air conditioning return vents are not
located in the immediate vicinity of the fireplace.
• Avoid installing the fireplace near doors, walkways or small
isolated spaces.
• Recessed lighting should be a “sealed can” design; attic
hatches weather stripped or sealed; attic mounted duct
work and air handler joints and seams taped or sealed.
• Basement installations should be avoided due to stack
effect. Stack effect creates negative pressure in lower
levels. Hearth & Home Technologies recommends the
use of direct vent fireplaces in basements.
Asphyxiation Risk
Negative pressure can cause spillage of
combustion fumes and soot. Fire needs to draft
properly for safe operation.
WARNING
Check building codes prior to installation.
• Installation MUST comply with local, regional,
state and national codes and regulations.
• Consult insurance carrier, local building inspector,
fire officials or authorities having jurisdiction about
restrictions, installation inspection and permits.
CAUTION
When planning a fireplace installation, it is necessary to de-
termine the following information before installing:
• Where the fireplace is to be installed. See Sections
3 and 4.
• The vent system configuration to be used. See Sections
5 and 6.
• Gas supply piping. See Section 7.
• Framing and finishing details. See Sections 3 and 8.
• Whether optional accessories are desired. See
Section 12.

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
6
Location of the fireplace and chimney will affect performance.
As shown in Figure 2.1 the chimney should:
• Be installed through the warm airspace enclosed by the
building envelope. This helps to produce more draft,
especially during lighting and die-down of the fire.
• Penetrate the highest part of the roof. This minimizes the
effects of wind turbulence.
• Be located away from trees, adjacent structures, uneven
roof lines and other obstructions.
Offsets can restrict draft so their use should be minimized.
Consider the fireplace location relative to floor and ceiling
and attic joists.
Recommended
Location
Marginal
Location
Location
Not
Recommended
Recommended
Location
Multi-level Roofs
Windward
Leeward
Outside Air Intake
Location
Not
Recommended
Figure 2.1 Recommended Chimney Locations

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 7
C. Typical Fireplace System
The Heatilator fireplace system consists of the following:
• Fireplace/integral grate/refractory/outside air system
• Chimney termination cap
• Chimney system (SL1100 series pipe NOT approved for Canada)
• Hearth extension
Termination cap
Chimney penetrates roof
preferably without affecting
roof rafters
Offset/Return (with hanger straps)
Framing headed off
in ceiling joists
Enclosed space above
and around fireplace
Mantel and surround
Decorative facing
and trim
Hearth extension
Factory-built fireplace
Protective metal
hearth strip(s)
Outside
combustion air
Combustible
framing/header
on top of
V-shaped
standoffs
(spacers)
Chimney system
(SLA10 not shown)
Ceiling firestop
on floor of attic
Support straps
on rafter supports
chimney (not shown)
Non-combustible
roof flashing maintains
minimum clearance
around chimney
Additional lateral
support for chimney
above roof (or enclosed
in chase) if needed
Attic insulation shield (not shown) must
be used here to keep insulation away
from chimney if attic is insulated
Storm Collar
Figure 2.2 Typical Fireplace System
Optional components include:
• Glass doors
• Chimney air kit (required in Canada)
• SLA10 11-10 in./279-254 mm (required in Canada)

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
8
Before beginning the installation be sure the following tools
and building supplies are available:
Reciprocating saw Framing material
Pliers High temp caulking material
Hammer Gloves
Phillips screwdriver Framing square
Flat blade screwdriver Electric drill and bits
Plumb line Safety glasses
Level Tape measure
1/2-3/4 in. length, #6 or #8 self-drilling screws
Misc. screws and nails
• Keep fireplace dry.
• Mold or rust may cause odors.
CAUTION
E. Inspect Fireplace and Components
• Carefully remove the fireplace and components from the
packaging.
• The vent system components and doors are shipped in
separate packages.
• Report to your dealer any parts damaged in shipment.
• Read all the instructions before starting the installation.
Follow these instructions carefully during the
installation to ensure maximum safety and benefit.
Fire Risk
Explosion Risk
Inspect fireplace and components for
damage. Damaged parts may impair safe
operation.
• Do NOT install damaged components.
• Do NOT install incomplete components.
• Do NOT install substitute components
Report damaged parts to dealer.
WARNING
D. Tools and Supplies Needed

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 9
3
3 Framing and Clearances
A. Selecting Fireplace Location
Several options are available to you when choosing a loca-
tion for your fireplace. This fireplace may be used as a room
divider, installed along a wall, across a corner or used in an
exterior chase. See Figure 3.1.
66 in.
(1676 mm)
42 in.
(1067 mm)
20 in. (508 mm)
(hearth
extension)
64 in.
(1626 mm)
12 in. (305 mm)
min. to
perpendicular
wall.
Figure 3.1 Fireplace Locations
Fire Risk
Provide adequate clearances.
• Around air openings
• To combustibles
• For service access.
Locate fireplace away from traffic areas.
WARNING Note:
• Illustrations and photos reflect typical installations
and are FOR DESIGN PURPOSES ONLY.
•Illustrations/diagrams are not drawn to scale.
•Actual installation/appearance may vary due to
individual design preference.
• Hearth & Home Technologies reserves the right to
alter its products.
Locating the fireplace in a basement, near frequently opened
doors, central heat outlets or returns, or other locations of
considerable air movement can affect the performance and
cause intermittent smoke spillage from the front of the fire-
place. Consideration should be given to these factors before
deciding on a location. See Sections 2 and 10.
Note: 1/2 in. (13 mm) min. dis-
tance from fireplace to
combustible materials.
Note: In addition to these fram-
ing dimensions, also
reference the following
sections:
• Clearances (Sec-
tion 3.B.)
• Mantel Projections
(Section 8.C.)
• Fireplace Dimensions
(Section 12.A.)

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
10
B. Clearances
2 in. (51 mm) min.
0 in. to level
of standoffs
Attic
Insulation
Shield
Ceiling Firestop
(ceiling)
(roof)
(attic)
(ceiling)
Ceiling Firestop Offset/Return with
hanger straps
Storm Collar
Roof Flashing
1/2 in. (13 mm) to side of appliance
2 in. (51 mm) min.
2 in. min.
(51 mm)
Must have 2 in. (51 mm)
minimum clearance
to header
0 in.
to floor
2 in. (51 mm) min.
2 in. (51 mm) min. 2 in. (51 mm) min.
2 in. (51 mm) min.
Figure 3.2 Clearances to Combustible Materials
Fire Risk
• Comply with all minimum clearances to combustibles as specified.
• Framing or finishing material used on the front of, or in front of, the
appliance closer than the minimums listed, must be constructed entirely
of noncombustible materials (i.e., steel studs, concrete board, etc.).
Failure to comply may cause fire.
WARNING
Note: Chimney air kit and 11-10 in. (279-254 mm) adapter not
shown but required in Canada.

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 11
C. Sidewalls/Surrounds
Adjacent combustible side walls must be located a minimum of 12 in. (305 mm) from the fireplace opening. See Figure 3.3.
If you are using a decorative surround constructed of combustible material, it must be located within the shaded area de-
fined in Figure 3.3. Short stub walls are also acceptable if they are contained within the shaded area.
D. Frame the Fireplace
Figure 3.4 shows a typical framing (using 2 x 4 lumber) of the fireplace, assuming combustible materials are used. All re-
quired clearances to combustibles around the fireplace must be adhered to. See Figure 3.2. Any framing across the top of
the fireplace must be above the level of the top standoffs.
50 deg.
37 deg.
Brick
Front
48 in.
(1219 mm)
(framing)
42 in.
(1067 mm)
(opening)
9-3/4 in.
(248 mm)
14-3/8 in.
(365 mm)
12 in.
(305 mm)
4 in.
(102 mm)
Flush
Front
12 in.
(305 mm)
Figure 3.3 Sidewalls and Surrounds
You must maintain
2 in. (51 mm) min. air space
clearance from the
chimney to the
enclosure.
27 in.
(686 mm)
Note: Fireplace
Header cannot be
positioned until after
the fireplace assembly
is in place.
12 in. (305 mm) max.
48 in.
(1219 mm)
Figure 3.4 Framing the Fireplace

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
12
E. Construct the Chase
A chase is a vertical boxlike structure built to enclose the fire-
place and/or its vent system. Vertical chimneys that run on
the outside of a building must be installed inside a chase.
Construction of the chase may vary with the type of build-
ing. These instructions are not substitutes for the require-
ments of local building codes. Local building codes MUST
be checked.
Chases should be constructed in the manner of all outside
walls of the home to prevent cold air drafting problems. The
chase should not break the outside building envelope in any
manner. All outside walls need to be insulated.
Building codes require false ceiling and ceiling firestops at
each floor of the chase or every 10 ft (3.05 m) of clear space
to control spread of fire.
Walls, ceiling, base plate and cantilever floor at the first level
of the chase should be insulated. See Figure 3.5. Vapor and
air infiltration barriers should be installed in the chase as per
regional codes for the rest of the home. Additionally, Hearth
& Home Technologies recommends that the inside surfac-
es be sheet rocked and taped (or the use of an equivalent
method) for maximum air tightness.
Attic
Insulation
Shield
Chimney
Ceiling
Firestop
Tabs
False Ceiling
False Ceiling
Insulation
Insulation
Ceilng
Firestop
Metal Chase Top
Round Termination Cap
False Ceiling
Figure 3.5 Chase Assembly
F. Chimney Requirements
When planning your fireplace location, the chimney con-
struction and necessary clearances must be considered.
The fireplace system and chimney components have been
tested to provide flexibility in construction. Vertical distances
are measured from the base of the fireplace as shown in
Figure 5.2.
12
Figure 3.6 Chase Constructions
1. Chimney offset through exterior wall and enclosed in
chase.
2. Chase constructed on roof.
Gas line holes and other openings should be caulked with
high temperature caulk or stuffed with unfaced fiberglass in-
sulation. If the fireplace is being installed on a cement slab,
we recommend that in cold climates, a sheet of plywood or
other raised platform be placed underneath to prevent con-
ducting cold up into the room.
Two examples of chase applications are shown in Fig-
ure 3.6.
ft meters
a. Minimum overall straight height 14.0 4.27
b. Minimum height with offset/return 16.5 5.03
c. Maximum height 90.0 27.43
d. Maximum chimney length between an offset and
return
20.0 6.1
e. Maximum distance between chimney stabilizers 35.0 10.67
f. Double offset/return minimum height 22.0 6.71
g. Maximum unsupported chimney length between the
offset and return
6.0 1.83
h. Maximum unsupported chimney height above the
fireplace
35.0 10.67
i. Maximum unsupported chimney above roof 6.0 1.83
Note: A maximum of two pairs offsets and returns may be
used.

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 13
4
4 Installation of Fireplace
A. Install the Outside Air Kit
This fireplace will operate correctly only if adequate ventila-
tion is provided to allow proper draft to the fireplace system.
See Section 2.
Using an outside air kit is highly recommended to minimize
the effects of negative pressure within the structure. We
recommend you utilize the shortest duct run to optimize the
performance of the outside air kit. Cold air flow can be mini-
mized by putting a small dip in the duct creating a cold air
trap. This trap can also help prevent heat build-up and ex-
hausting out the intake due to the stack effect. The outside
air kit inlet should be positioned in a manner that will not al-
low snow, leaves, etc. to block the inlet. In some installations
the air duct may need to be run vertically. In such an instal-
lation, a 3 ft (.914 m) height difference must be maintained
from the top of the uppermost chimney section to the outside
combustion air inlet. See Figure 4.2.
See Figure 4.3 for proper placement of outside air inlet.
The outside air kit is installed on the left hand side of the
fireplace. See Figure 4.4 for handle location/operation.
Risk of Smoke Spillage
Outside air inlet must be located to prevent blockage
from:
• Leaves
• Snow/ice
• Other debris
Blockage may cause combustion air starvation.
CAUTION
Sharp Edges
• Wear protective gloves and safety glasses
during installation.
CAUTION
Fire Risk
Asphyxiation Risk
Do not draw outside combustion air from:
• Wall, floor or ceiling cavity.
• Enclosed space such as an attic or
garage.
• Close proximity to exhaust vents or
chimneys.
Fumes or odor may result.
WARNING
Outside Air
Shield
Outside Air
Plate
Assembly
2 Wire Ties
Flexible Duct
(not supplied)
Figure 4.1 Outside Air Installation

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
14
Figure 4.4 Locating the Outside Air Control
(Push slider to open.)
open
close
Outlet placed
higher than 3 ft
below the
termination cap
Attic space
Garage or
combustible
liquids storage
Outlet blocked by
snow, leaves, etc.
Clear area
outside
house or in
ventilated
crawl space
YES
NO
NO
NO
NO
Use only duct materials specified
by manufacturer (preferably with
short run or mainly straight duct,
except small dip for cold air trap
which will help prevent flow of cold air).
Factory-built
fireplace
Figure 4.3 Outside Combustion Air Placement
3 ft min. from top of
uppermost chimney
section to air inlet.
Attic insulation shield
must be used to keep
insulation away from
chimney.
Ceiling firestop
on floor of attic.
Figure 4.2 Outside Air Inlet Locations
11-10 in./279-254 mm
adaptor not shown.
Note: Chimney air kit and 11-10 in. (279-
254 mm) adapter required in Canada.

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 15
B. Secure the Fireplace
• Position the Fireplace
This fireplace may be placed on either a combustible or
noncombustible continuous flat surface. Follow the in-
structions for framing in Section 3.D. Slide the fireplace
into position. Be sure to provide the minimum air clear-
ance at the sides and back of the fireplace assembly.
See Section 3.B.
Included with your fireplace you will find four metal
hearth strips measuring approximately 28 in. x 4 in.
(711 mm x 102 mm). These strips are used to provide
added protection where the fireplace and the hearth ex-
tensions meet.
Slide each metal strip 2 in. (51 mm) under the front
edge of the fireplace. The individual pieces must over-
lap each other by 1 in. (25 mm) minimum in the middle
of the fireplace to provide continuous coverage of the
floor. See Figure 4.3. These metal strips should extend
from the front and sides of the fireplace opening by 2 in.
(51 mm).
Note: When elevating the fireplace above the hearth exten-
sion the front of the elevated platform must be protected with
a protective metal hearth strip as shown in Figure 4.6.
Raised Platform
Floor
2 in.
(51 mm)
1 in. (25 mm) min.
overlap
2 in.
(51 mm)
Top piece must overlap
bottom piece
Figure 4.6 Protect the Front of an Elevated Platform
• Level the Fireplace
Level the fireplace side-to-side and front-to-back. Shim
with noncombustible material, such as sheet metal, as
necessary. Secure the fireplace (using the nailing flang-
es located on either side of the fireplace) to the vertical
framing.
Important: To ensure proper fit of the glass doors, check
the fireplace openings for square. Measure diagonal dis-
tances of each opening to make sure they are equal. If they
are not, continue to shim the fireplace until those diagonals
are equal.
1 in. (25 mm) overlap
Metal strips are placed 2 in. (51 mm) under the front
of the fireplace and must extend beyond the front
and sides of fireplace openings by 2 in. (51 mm).
Figure 4.5 Position the Protective Metal Hearth Strips
• Place the Protective Metal Hearth Strips
Fire Risk!
• Prevent contact with sagging, loose
insulation.
• Do NOT install against vapor barriers or
exposed insulation.
WARNING
Fire Risk!
• Metal hearth strips MUST be installed.
Sparks or embers may ignite flooring.
WARNING

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
16
NOTE:
•Chimney performance may vary.
•Trees, buildings, roof lines and wind conditions affect
performance.
•Chimney height may need adjustment if smoking or
overdraft occurs.
Chimney must extend
beyond combustible
roof structure
Maintain minimum
height of chimney
above roof
Additional
support for
tall chimneys
Install roof flashing
according to minimum
requirements
Maintain minimum
clearances to
combustibles as
specified
Offsets/returns
may not exceed
30° from vertical
Lock chimney
sections together
firmly to resist
movement
Ceiling firestops
are required where
chimney passes
through ceiling or
floor
Support straps for offsets/
returns must be secured
to adequate framing
Termination Cap
Storm Collar
Figure 5.1 Typical Chimney System - Guidelines for Chimney System Installation
5
5 Chimney Assembly

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 17
A. Chimney Requirements
Vertical distances are measured from the base of the fire-
place as shown in Figure 5.2.
To determine the chimney components needed to complete
your particular installation, follow the steps below:
• Determine the total vertical height of the fireplace
installation. This dimension is measured from the base of
the fireplace assembly to the point where the smoke exits
the termination cap.
• Subtract the effective height of the fireplace assembly from
the overall height of the fireplace installation (measured
from the base of the fireplace to the bottom of the
termination cap).
• Refer to Table 5.1 to determine what components must
be selected to complete the fireplace installation.
• Determine the number of ceiling firestops, stabilizers,
roof flashing, etc. required to complete the fireplace
installation.
d & g
Ceiling Firestop h
i
58-7/8 in.
(1495 mm)
Effective
Height
a,b,c,f
11-10 in. (279-254 mm)
adapter required in
Canada.
Figure 5.2 Chimney Requirements (refer to list in Sect. 5.A.)
Table 5.1
• Do NOT connect this fireplace to a chimney flue
servicing another appliance.
• Do NOT connect to any air distribution duct or
system.
CAUTION
Fire Risk
• Must maintain 2 in. (51 mm) air clearance
to insulation and other combustible
materials.
WARNING
ft meters
a. Minimum overall straight height 14.0 4.27
b. Minimum height with offset/return 16.5 5.03
c. Maximum height 90.0 27.43
d. Maximum chimney length between an offset and
return
20.0 6.1
e. Maximum distance between chimney stabilizers 35.0 10.67
f. Double offset/return minimum height 22.0 6.71
g. Maximum unsupported chimney length between the
offset and return
6.0 1.83
h. Maximum unsupported chimney height above the
fireplace
35.0 10.67
i. Maximum unsupported chimney above roof 6.0 1.83
Note: A maximum of two pairs offsets and returns may
be used.
HEIGHT OF CHIMNEY
COMPONENTS in. mm
US Canada
Chimney Stabilizer
SL11 SL4 4-3/4 121
Ceiling Firestops
FS538 FS538 0 0
FS540 FS540 0 0
Offsets/Returns
SL1130 SL430 14-1/2 368
Roof Flashing
RF570 RF570 0 0
RF571 RF571 0 0
Chimney Sections*
SL1106 SL406 4-3/4 121
SL1112 SL412 10 - 3/4 27 3
SL1118 S L418 16 - 3/4 42 5
SL1136 SL436 34-3/4 883
SL1148 SL448 46-3/4 1187
n/a SLA10 16-3/4 425
* Dimensions reflect effective height.

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
18
B. Using Offsets/Returns
To bypass any overhead obstructions, the chimney may be
offset using an offset/return.
An offset and return may be attached together or a chimney
section(s) may be used between an offset and return.
Perform the following steps to determine the correct chim-
ney component combination for your particular installation:
• Measure how far the chimney needs to be shifted to enable
it to avoid the overhead obstacle. See Figure 5.3. Use
dimension “A” to determine chimney section required to
achieve the needed shift.
• After determining the offset dimension, refer to Table 5.2
and find the “A” dimension closest to but not less than the
distance of shift needed for your installation.
• The “B” dimension that coincides with the “A” dimension
represents the required vertical clearance that is needed
to complete the offset and return.
• Read across the chart and find the number of chimney
sections required and the model number of those particular
chimney parts.
• Whenever the chimney penetrates a floor/ceiling, a ceiling
firestop must be installed.
• The effective height of the fireplace assembly is measured
from the base of the fireplace to the top of the starter collar.
See Dimensions in Section 12.
Table 5.2
A
B
1-1/4 in. (32 mm)
OVERLAP
Figure 5.3 Chimney Offset/Return
Example: Your “A” dimension from Figure 5.3
is 14 1/2 in. (368 mm). Using Table 5.2 the
dimension closest to, but not less than 14 1/2 in.
(368 mm) is 15 3/4 in. (400 mm) using a 30°
offset/return. It is then determined from the table
that you would need 36 5/8 in. (930 mm) (Dimen-
sion “B”) between the offset and return. The
chimney components that best fit your application
are two SL1112s or SL412s.
Fire Risk
• Draft will be restricted if offset/returns
greater than 30° are used.
WARNING
AB
SL1106
SL406
SL1112
SL412
SL1118
SL418
SL1136
SL436
SL1148
SL448in. mm in. mm
47/8124177/8454-----
7 1/4 184 2 2 559 1 - - - -
9 3/4 248 26 1/8 664 2 - - - -
10 1/4 260 27 1/4 692 - 1 - - -
12 3/4 324 31 3/8 797 1 1 - - -
13 1/4 337 32 3/8 822 - - 1 - -
15 3/4 400 36 5/8 930 - 2 - - -
18 1/8 460 40 3/4 1035 1 2 - - -
18 3/4 476 41 3/4 1060 - 1 1 - -
21 3/4 552 47 1194 - - 2 - -
22 1/4 565 4 8 1219 - - - 1 -
24 3/4 629 52 1/8 1324 1 - - 1 -
27 3/4 705 57 3/8 1457 - 1 - 1 -
281/4718583/81483----1
303/4781621/215881---1
33 3/4 857 67 3/4 1721 - 1 - - 1
36 3/4 933 73 1854 - - 1 - 1
39 3/4 1010 78 1/8 1984 - - - 2 -
41 1/8 1045 82 3/8 2092 1 - - 2 -
453/41162881/22248---11
48 1/8 1222 92 3/4 2356 1 - - 1 1
513/41314987/82511----2
Proper assembly of air cooled chimney parts results in an overlap of chimney joints
of 1-1/4 in. (32 mm). Effective length is built into this table.

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07 19
C. Assemble the Chimney Sections
Attach either a straight chimney section or an offset to the
top of the fireplace (depending on your installation require-
ment). Chimney sections are locked together by pushing
downward until the top section meets the stop bead on the
lower section.
The inner flue is placed to the inside of the flue section below
it. The outer casing is placed outside the outer casing of the
chimney section below it. See Figure 5.4.
D. Install the Ceiling firestops
• Mark and cut an opening in the ceiling for the ceiling
firestop being used. See Figure 5.5.
• Frame the opening with the same size lumber used in the
ceiling joists.
• Install the ceiling firestop.
Note: The ceiling firestop MUST be nailed to the bottom
of the ceiling joists EXCEPT when the space above is
uninsulated and the attic insulation shield is not being used
(see Figure 5.5). When the attic insulation shield is used
the ceiling firestop may be above or below the joist of an
insulated ceiling.
Note: You must provide support for the pipe during con-
struction and check to be sure inadvertent loading has not
dislodged the chimney section from the fireplace or at any
chimney joint.
Note: Inner flue and outer liner sections cannot be disas-
sembled once locked together. Plan ahead to ensure the
proper installation height is achieved with the selected
chimney components.
• Ceiling firestops must be used at ceiling/floor.
• Chase construction requires ceiling firestops at each
floor or every 10 ft (3.05 m) of clear space.
• Use same dimensional lumber as joists.
Ceiling firestop slows spread of fire and reduces cold air
infiltration.
CAUTION
Figure 5.4 Assembling Chimney Sections
ROOM ABOVE (non-insulated ceiling)
ATTIC ABOVE (insulated ceiling)
B
A
Ceilng firestop from
bottom
Ceiling firestop from
top
When attic insulation
shield not used
Note: Use same dimensional lumber for framing
ceiling firestop and joists.
Figure 5.5 Installing the Ceiling Firestop
Fire Risk
Do NOT install substitute or damaged
chimney components.
• MUST use chimney system described in
this manual.
• NO OTHER chimney components may
be used.
Substitute or damaged chimney components
may impair safe operation.
WARNING Catalog #
AB
in.mmin.mm
FS538 17 432 17 432
FS540 17 432 26 660

Heatilator • ST42A US-CAN • 4012-039 Rev D • 11/07
20
6 Tabs bent
in 90°
Tabs bent in to
rest against pipe
Attic Insulation Shield
Ceiling Firestop
13 in.
(330 mm)
17 in. (432 mm)
diameter
Insulation
Insulation
Pipe
Pipe
Figure 5.7 Install Attic Insulation Shield Above the Ceiling
6 Tabs bent
in 90°
Tabs bent in to
rest against pipe
Attic Insulation Shield
Ceiling Firestop
13 in.
(330 mm)
17 in. (432 mm)
diameter
InsulationInsulation
Pipe
Pipe
Figure 5.8 Install Attic Insulation Shield Below the Ceiling
Fire Risk
• DO NOT pack insulation or other
combustibles: between ceiling firestops;
between chimney and attic insulation
shield.
• ALWAYS maintain specified clearances
around chimney and ceiling firestop
systems.
• Install ceiling firestops as specified.
Failure to keep insulation or other material
away from chimney pipe may cause fire.
WARNING
An insulation shield must be installed when there is a pos-
sibility of insulation coming into contact with the factory built
chimney system. Installation of a ceiling firestop is required
(see Figures 5.7 and 5.8).
• Roll the shield (around the chimney if already installed)
until you have a 3 in. (76 mm) overlap and the three holes
on each side match up (large holes on top).
• Insert three screws into the matching holes to form a
tube.
• Bend three tabs on the bottom of the tube inward to 90°
to maintain chimney clearance. See Figure 5.6.
• Rest the insulation shield on the ceiling firestop below.
• Bend the three short tabs at the top of the shield inward
to 90° to maintain the 2 in. (51 mm) clearance from the
chimney.
• Bend the remaining top tabs to just meet the pipe.
3 in. (76 mm)
overlap
Insert three
screws
Bend inward
90°
Bend remaining tabs
to rest against pipe to
prevent insulation
from falling in.
E. Install the Attic Insulation Shield
If you wish to make a custom shield or barrier, follow these
guidelines:
• Metal is preferred, although any material stiff enough to
hold up against the insulation can be used.
• The shield or barrier must be tall enough to extend above
the insulation and prevent blown-in insulation from spilling
into the cavity.
• Maintain specified cleaances around chimney.
• Check instructions and local codes for further details.
Figure 5.6 Prepare Attic Insulation Shield
¨
¨
¨