Heatilator ST42A User manual
1Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
WOODBURNING FIREPLACE
Fire Risk.
WARNING
For use with solid wood fuel only.
Model(s):
Installation Manual
Installation and Fireplace Setup
WARNING
HOT SURFACES!
Hot glass will cause burns.
• DO NOT
materials.
materials away.
INSTALLER: Leave this manual with party responsible for use and operation.
OWNER: Retain this manual for future reference.
ST42A
NOTICE: DO NOT discard this manual!
• DO NOT-
• DO NOT
warranty.
-
WARNING: If the information in these
or explosion may result causing property
damage, personal injury, or death.
Installationand s of thisshouldperformedy
2 Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
Safety Alert Key:
• DANGER! will result in death or serious injury.
• WARNING! result in death or serious injury.
• CAUTION!
• NOTICE:
Table of Contents
2 Getting Started
C. Tools and Supplies Needed 8
3 Framing and Clearances
4 Chimney and Termination Requirements
5 Chimney Installation
G. Roof Penetration 22
6 Shrouds
7 Finishing
8 Fireplace Setup
9 Reference Materials
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
Customer:
Lot/Address
Model (circle one):
YES IF NO, WHY?
WARNING! Risk of Fire or Explosion! Failure to install fireplace acording to these instructions can lead to a fire or
explosion.
Firestops installed.
ATTENTION INSTALLER:
Follow this Standard Work Checklist
his installation
manual.
Date Installed:
Location of Fireplace:
Installer:
Dealer/Distributor Phone #
Serial #:
Termination installed.
Fireplace Install
Chimney
Shrouds Section 6 (Pg. 25)
Fi i hi
S ti 7 (P 27)
Optional doors properly installed.
Grate is properly installed.
Comments:
Finishing Section 7 (Pg. 27)
Fireplace Setup Section 8 (Pg. 34)
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
WARNING! Risk of Fire! Hearth & Home Technologies
disclaims any responsibility for, and the warranty and
agency listing will be voided by the following actions.
DO NOT:
• install other than as instructed by Hearth & Home
Technologies
• operate the fireplace without fully assembling all
components
• install any component not approved by Hearth & Home
Technologies
• install parts or components not Listed or approved
Improper installation, adjustment, alteration, service or
maintenance can cause injury or property damage. For
installer, service agency or your dealer.
B. Non-Combustible Materials
- Steel - Iron
- Glass - Plasters
ASTM E 136, Standard
Test Method for Behavior of Metals, in a Vertical Tube
Furnace at 750° C
C. Combustible Materials
1
WARNING: This product and the fuels
used to operate this product (wood and
wood pellets), and the products of combus-
tion of such fuels, can expose you to chemi-
cals including carbon black, which is known
to the State of California to cause cancer
and carbon monoxide, which is known to
the State of California to cause birth defects
or other reproductive harm. For more infor-
mation go to: www.P65Warnings.ca.gov.
-
-
-
-
United States and Canada.
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
2 Getting Started
A. Typical Fireplace System
Figure 2.1 Typical Fireplace System
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Non-combustible
roof flashing maintains
minimum clearance
around chimney
Additional lateral
support for chimney
above roof (or enclosed
in chase) if needed
Ceiling firestop
on floor of attic
Support straps
on rafter support
chimney (not shown)
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
Chimney system
Attic insulation shield (not shown)
must be used here to keep
insulation away from chimney
if attic is insulated
Storm Collar
Chimney Air Kit
Required in
Canada. Outlet
must be no
less than 4 ft.
(1.322 m) off
ground level.
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
1/2 in. (13 mm)
all configurations
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 2.2 Fireplace Locations
NOTICE:
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.
NOTICE: In addition to these framing dimensions, also
reference the following section:
• Clearances (Section 3).
NOTICE:
A minimum 1/2 in. air clearance at the back and
-
tained.
Chimney sections at any level require a 2 in. mini-
mum air space clearance between the framing
and chimney sections.
B. Design and Installation Considerations
NOTICE: Check building codes prior to installation.
• Before installing
1. Selecting Fireplace Locations
2.2.
-
-
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
-
Marginal Location:
Marginal Location:
Figure 2.3 Recommended Chimney Locations
all
taped or sealed.
8 Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
C. Tools and Supplies Needed
Level Tape measure
D. Inspect Fireplace and Components
WARNING! Risk of Fire and/or Explosion! Damaged
parts could impair safe operation. DO NOT install dam-
-
place dry.
• Read all the instructions before starting the
installation. Follow these instructions carefully
during the installation to ensure maximum safety
E. Fireplace System Requirements
• Outside Air System
• Chimney System
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
3 Framing and Clearances
A. Appliance Dimensions/Weight
Gas
Knockout
Outside
Air
58-7/8 in.
(1496 mm)
(effective height)
38-3/8 in.
(975 mm)
11-3/4 in.
(298 mm)
8-5/8 in.
(219 mm)
13 in.
[330 mm]
dia.
42 in.
(1067 mm)
23 in.
(585 mm)
7-1/2 in.
(192 mm)
39-1/8 in.
(995 mm)
Gas
Knockout
8-3/8 in.
(213 mm)
14 in.
(356 mm)
8-3/8 in.
(213 mm)
14 in.
(356 mm)
47 in.
(1194 mm)
28 in.
(711 mm)
23-1/2 in.
(597 mm)
14 in.
(356 mm)
5-7/8 in.
(149 mm)
Figure 3.1 Appliance Dimensions
Model Pounds
Appliance Weight Table
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
B. Clearances
WARNING! Risk of Fire!
You must comply with all minimum air space clearances
DO NOT pack
required air spaces with insulation or other materials.
be constructed entirely of non-combustible materials (i.e.,
steel studs, concrete board, etc.). Failure to comply may
Minimum Clearances to Combustibles
WITHIN ENCLOSURE AREA
MANTEL
Figure 3.2 Clearances to Combustible Materials
(roof)
(insulation)
0 in. to level
of standoffs
Attic
Insulation
Shield
(ceiling)
(attic)
(ceiling)
Offset/Return (secured
with hanger straps)
Storm Collar
Roof Flashing
1/2 in. (13 mm) to
sides of appliance
Must have 2 in. (51 mm)
minimum clearance
to header
0 in.
to floor
2 in. (51 mm) min.
Shaded areas
represent
2 in. (51 mm) min.
air space clearance
required around pipe
Combustible Object
Adapter
Ceiling Firestop
48 in.
1219 mm
Note:
Canada.
11Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
C. Construct the Chase
-
-
-
-
-
lation.
Ceiling
Firestop
Metal Chase Top
Round Termination Cap
False Ceiling
Insulation in the
outside walls
of the chase
Attic
Insulation
Shield
Chimney
Ceiling
Firestop
Tabs
False Ceiling
False Ceiling
Insulation
Insulation
Figure 3.3 Chase Assembly
12
1. Chimney offset through exterior wall and
enclosed in chase.
2. Chase constructed on roof.
Figure 3.4 Chase Constructions
WARNING! You must install false ceilings and ceil-
WARNING! Risk of Fire! DO NOT
stop opening and chimney pipe except where they enter
the attic or leave the warm air envelope of the home (use
600° F sealant).
WARNING! Risk of Fire! You must maintain a minimum
2 in. (51 mm) air space clearance to insulation and other
materials surrounding the chimney system.
prevent accidental contact with chimney system.
• The chase must be properly blocked to prevent blown
insulation or other combustibles from entering and
• Failure to prevent contact between insulation or other
materials and chimney system may cause overheating
12 Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
D. Frame the Fireplace
NOTICE:
platform.
WARNING! Risk of Fire! You must comply with all mini-
mum air space clearances to combustibles. DO NOT pack
required air spaces with insulation or other materials.
WARNING! Risk of Fire! Comply with all minimum clear-
• A minimum 1/2 in. (13 mm) air clearance must be
• Chimney sections at any level require a 2 in. (51 mm)
minimum air space clearance between the framing and
chimney section.
-
CAUTION! Risk of Cuts/Abrasions. Wear protective gloves
and safety glasses during installation. Sheet metal edges
are sharp.
WARNING! Risk of Fire! Prevent contact with sagging,
loose insulation.
• DO NOT install against vapor barriers or exposed
insulation.
• Secure insulation and vapor barriers.
• Provide minimum air space clearances at the sides and
E. Secure and Level the Fireplace
-
-
17 in. (368 mm)
framing
27 in.
(686 mm)
Note: Fireplace
header cannot be
positioned until after
the fireplace assembly
is in place and set on
edge. The 2 x 4s above
the header will lay flat.
12 in. (305 mm) max.
48 in.
(1219 mm)
3-1/2 in.
(89 mm)
3-1/2 in.
(89 mm)
Figure 3.5 Framing the Fireplace
1/2 in.
(13 mm)
Fireplace must be set out
1/2 in. (13 mm) in front of
the face of the framing
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
Protective metal strips are placed 2 in. (51 mm) under the
front of the fireplace and must extend beyond the front
and sides of fireplace opening by 2 in. (51 mm).
1 in. (25 mm)
overlap
Raised Platform
Floor
2 in.
(51 mm)
1 in. (25 mm) min.
overlap
2 in.
(51 mm)
Top piece must overlap
bottom piece
Figure 3.7 Protect the Front of an Elevated Platform
F. Protective Metal Hearth Strips
Figure 3.6 Position the Protective Metal Hearth Strips
WARNING! Risk of Fire! Protective metal hearth
strips MUST be installed on combustible surfaces. DO
NOT cover metal strips with combustible materials.
WARNING! "High temperatures, sparks,
embers or other burning material falling from the
surfaces.
• Protective metal hearth strips MUST be installed.
• Hearth extensions MUST be installed exactly as
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
G. Outside Air Kit
-
inlet hood.
inlet hood.
Installation
outside air inlet hood.
CAUTION! Risk of Cuts/Abrasions. Wear protective
gloves and safety glasses during installation. Sheet metal
edges are sharp.
CAUTION! #$%"DO NOT draw
enclosed spaces such as an attic or garage.
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3 ft min. from
top of uppermost
chimney section
to air inlet.
Figure 3.9 Outside Air Inlet Locations
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
Factory-built
fireplace
• Use UL181 Class 1 or Class 0 rigid or flexible ducting.
• Install with short run and add a P-trap which will help
prevent flow of cold air.
• Secure flex duct with screws or wire ties.
Figure 3.8 Outside Air Installation
• DO NOT place outside air inlet hood close to exhaust
vents or chimneys. Fumes or odor could be drawn into
• Locate outside air inlet hood to prevent blockage from
leaves, snow/ice, or other debris. Blockages could cause
combustion air starvation.
Typical Outside Air
Installation
Recommend
around 24 inches
for a minimum bend
Figure 3.10 Outside Air Installation with Cold Air Trap
Note:
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
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 4.1 Chimney Requirements
NOTICE:
may be used.
WARNING! Risk of Fire! You must maintain 2 in. (51 mm)
air space clearance to insulation and other combustible
materials around the chimney system. Failure to do so
NOTICE: You must provide support for the pipe during
construction and check to be sure inadvertent loading has
any chimney joint.
A. Chimney Requirements
4 Chimney and Termination Requirements
Table 4.2 Chimney Component Dimensions
Table 4.1 Chimney Requirements
ft meters
a.
d.
return
e.
f.
h.
i.
HEIGHT OF CHIMNEY COMPONENTS in. mm
US Canada ONLY
Chimney Stabilizer
SL11 121
Chimney Sections*
121
SL1112
SL1118
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
WARNING! Risk of Fire! DO NOT
Straight chimney sections may be secured with screws. Keep chimney sections from separating or twisting.
A
B
1-1/4 in. (32 mm)
OVERLAP
Example:
return.
two SL1112s.
Note:
for Canada ONLY.
AB
SL1106
SL406
SL1112
SL412
SL1118
SL418
SL1136
SL436
SL1148
SL448in. mm in. mm
-----
22 1 - - - -
2 - - - -
- 1 - - -
1 1 - - -
822 - - 1 - -
- 2 - - -
1 2 - - -
- 1 1 - -
- - 2 - -
- - - 1 -
1 - - 1 -
-1-1-
----1
1 - - - 1
- 1 - - 1
- - 1 - 1
- - - 2 -
1 - - 2 -
- - - 1 1
1222 1 - - 1 1
----2
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
Slanted Roofs
Flat Roofs
Chimney must
extend 3 ft (.9 m)
above the roof
Chimney must extend 2 ft (.6 m)
above any portion of the roof or
adjacent structures within
10 ft (3 m) of the chimney
Chimney must
extend 3 ft (.9 m)
above the roof
Chimney must extend 2 ft (.6 m)
above any portion of the roof or
adjacent structures within
10 ft (3 m) of the chimney
Multiple Chimney Locations
AB
6 in. (minimum) up to 20 in.
152 mm/508 mm
18 in. minimum
457 mm
20 in. and over 0 in. minimum
Gas, Wood or Fuel Oil
Termination Cap
Wood
Minimum
(See
illustration
above)
B
Gas
Termination
Cap **
A *
Perpendicular Wall
*If using decorative cap cover(s), this distance may need to be
increased. Refer to the installation instructions supplied with the
decorative cap cover.
** In a staggered installation with both gas and wood terminations, the
wood termination cap must be higher than the gas termination cap.
Figure 4.3 Multiple Chimney Locations
C. Termination Requirements
18 Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
5 Chimney Installation
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
(not shown) must be
secured to adequate framing
Termination Cap
Storm Collar
Offsets/returns must be
secured with screws
(outer pipe only)
Attic shield
The chimney must be
enclosed from the
replace to the attic
maintaining the 2
inch clearances.
Figure 5.1 Typical Chimney System - Guidelines for Chimney System Installation
NOTICE: Chimney performance may vary.
• Chimney height may need adjustment if smoking or overdraft occurs.
A. Typical Chimney System
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
C. Install Chimney Air Kit
NOTICE: Chimney sections cannot be disassembled once
locked together. Plan ahead!
and will not separate.
fasten to studs or joists.
B. Assemble Chimney Sections
-
-
WARNING! Risk of Fire! DO NOT install substitute or
damaged chimney components.
Figure 5.2 Assembling Chimney Sections
Heatilator • ST42A Installation Manual • 4012-051 • Rev O • 02/22
E. Install Ceiling Firestops
CAUTION! Risk of Fire!
the joists.
ROOM ABOVE (non-insulated ceiling)
ATTIC ABOVE (insulated ceiling)
B
A
Ceilng firestop
attached to bottom
of framing
Ceiling firestop
attached to top of
framing
Note: Use same dimensional lumber for framing
ceiling firestop and joists.
2 in. (51mm)
clearance
2 in. (51mm)
clearance
WARNING! Risk of Fire! DO NOT seal area between
-
ter the attic or leave the warm air envelope of the home
(use 600° F sealant).
Figure 5.4 Installing the Ceiling Firestop
-
-
WARNING! Risk of Fire!
In length).
• Secure returns with strapping.
• Straight chimney sections may be secured with screw
(not to exceed 1/2 in./13 mm In length) at the joints.
• Keep chimney sections from separating or twisting.
Ceiling
Firestop
Straps
Optional
Additional
Support
Joint
Band
(Optional)
Figure 5.3 Secure the Chimney
Catalog #
AB
in. mm in. mm
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