Bryant 351DAS Installation manual

NOTE: Read the entire instruction manual before starting the
installation.
Index Page
DIMENSIONAL DRAWING........................................................2
SAFETY CONSIDERATIONS..................................................1-3
Clearances to Combustibles......................................................3
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS....3-4
INTRODUCTION.......................................................................4-5
APPLICATIONS ........................................................................4-7
General......................................................................................5
Condensate Trap Installation.................................................5-7
LOCATION ................................................................................8-9
General...................................................................................8-9
Furnace Location Relative to Cooling Equipment..................9
Hazardous Locations.................................................................9
INSTALLATION......................................................................9-12
Installation In Downflow Application................................9-10
Filter Arrangement..................................................................11
Gas Piping..........................................................................11-12
ELECTRICAL CONNECTIONS...........................................12-13
115-v Wiring...........................................................................13
24-v Wiring.............................................................................13
Accessories..............................................................................13
Wiring Diagram......................................................................14
DIRECT VENTING ...............................................................13-21
Removal of Existing Furnaces from
Common Vent Systems................................................13-15
Combustion-Air and Vent Piping .....................................15-19
Concentric Vent and Combustion-Air Termination
Kit Installation..............................................................19-21
CONDENSATE DRAIN..............................................................21
General....................................................................................21
Application..............................................................................21
Condensate Drain Protection..................................................21
SEQUENCE OF OPERATION..............................................21-23
Heating Mode....................................................................21-22
Cooling Mode .........................................................................22
Continuous Blower Mode.......................................................22
Heat Pump Mode....................................................................22
Component Test.................................................................22-23
START-UP PROCEDURES ..................................................23-27
General....................................................................................23
Prime Condensate Trap With Water......................................23
Purge Gas Lines......................................................................23
Adjustments .......................................................................27-32
Set Gas Input Rate ............................................................27-32
Set Temperature Rise..............................................................32
Blower Off Delay (Heat Mode).............................................32
Set Thermostat Heat Anticipator............................................32
CHECK SAFETY CONTROLS ............................................32-33
Check Primary Limit Control.................................................32
Check Pressure Switch ...........................................................33
CHECKLIST................................................................................33
SAFETY CONSIDERATIONS
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified person-
nel should install, repair, or service heating equipment. Untrained
personnel can perform basic maintenance functions such as clean-
ing and replacing air filters. All other operations must be per-
formed by trained service personnel. When working on heating
equipment, observe precautions in literature, on tags, and on labels
attached to or shipped with unit and other safety precautions that
may apply.
Follow all safety codes. In the United States, follow all safety
codes including the National Fuel Gas Code (NFGC) NFPA No.
54-1996/ANSI Z223.1-1996 and the Installation Standards, Warm
Air Heating and Air Conditioning Systems (NFPA 90B)
ANSI/NFPA 90B. In Canada, refer to the current edition of the
National Standard of Canada CAN/CGA-B149.1- and .2-M95
Natural Gas and Propane Installation Codes (NSCNGPIC). Wear
safety glasses and work gloves. Have fire extinguisher available
during start-up and adjustment procedures and service calls.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol on unit or in instructions and manuals,
be alert to potential for personal injury.
Understand the signal words DANGER, WARNING, and CAU-
TION. These words are used with the safety-alert symbol. DAN-
GER identifies most serious hazards which will result in severe
A93040
®ama
CANADIAN GAS ASSOCIATION
APPROVED
R
As an ENERGY STARSM
Partner, Bryant Heating &
Cooling Systems Com-
pany has determined that
this product meets the EN-
ERGY STAR guidelines
for energy efficiency. REGISTERED QUALITY SYSTEM
installation, start-up,
and operating instructions
DOWNFLOW MANUFACTURED (MOBILE)
AND MODULAR HOME DIRECT-VENT
CONDENSING GAS FURNACE
Cancels: New II 351D-80-1
2-99
351DAS
Series A
—1—

Fig. 1—Dimensional Drawing
DIMENSIONS (IN.)
UNIT SIZE A D E
036080 17-1/2 15-7/8 16 048080 17-1/2 15-7/8 16 060080 21 19-3/8 19-1/2
A98647
24 1⁄2"
27 9⁄16"
TYP
27 5⁄8"
30 13⁄16"
32 5⁄8"
TYP
29 11⁄16"
TYP
33 1⁄4"
TYP
7⁄8-IN. DIA
ACCESSORY
POWER ENTRY
7⁄8-IN. DIA
POWER CONN
CONDENSATE DRAIN
TRAP LOCATION
26 15⁄16"
24 1⁄2"
22 5⁄16"
2-IN. COMBUSTION -AIR CONN
1⁄2-IN. DIA
GAS CONN
2-IN. VENT CONN
1⁄2-IN. DIA
THERMOSTAT ENTRY
22 11⁄16"
OUTLET
26 15⁄16"
28 1⁄2"
22 5⁄16"
19"
13⁄16"
5⁄8"
39 7⁄8"
11⁄16"24 3⁄16"
INLET
18 1⁄4"
22 11⁄16"
2-IN.
COMBUSTION-
AIR CONN
1⁄2-IN. DIA
GAS CONN
7⁄8-IN. DIA
POWER CONN
1⁄2-IN. DIA
THERMOSTAT ENTRY
2-IN. VENT CONN
30 1⁄2"
OUTLET FLANGE AS SHIPPED (REMOVE IN FIELD)
E
INLET
11/16"
11/16"
D13/16"
13/16"
OUTLET
A
AIRFLOW
26 1⁄4"26 1⁄4"
CONDENSATE DRAIN TRAP LOCATION OR ALTERNATE 1⁄2
-IN. DIA GAS CONN
NOTES: Minimum return-air opening at furnace, based on metal  duct. If flex duct is used, see flex duct manufacturer's  recommendation for equivalent diameters:  1. For 800 CFM 16-in. round or 14- 1/2X 12-in. rectangle.
 2. For 1200 CFM 20-in. round or 14- 1/2X 19-1/2in. rectangle.
 3. For 1600 CFM 22-in. round or 14- 1/2X 23-1/4in. rectangle.
—2—

personal injury or death. WARNING signifies hazards which
could result in personal injury or death. CAUTION is used to
identify unsafe practices which would result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
CAUTION: Electrostatic discharge can affect electronic
components. Take precautions during furnace installation
and servicing to protect the furnace electronic control.
Precautions will prevent electrostatic discharges from
personnel and hand tools which are held during the
procedure. These precautions will help to avoid exposing
the control to electrostatic discharge by putting the
furnace, the control, and the person at the same electro-
static potential.
Fig. 2—Clearances to Combustibles A99001e
INSTALLATION
This forced air furnace is equipped for use with natural or propane gas at altitudes 0 - 10,000 ft (0 - 3,050m).
This furnace is for indoor installation in a manufactured (mobile) or modular home.
This furnace may be installed on combustible flooring in alcove or closet at minimum clearance from combustible material.
This appliance requires a special venting system. Refer to the installation instructions for parts list and method of installation. This furnace is for use with schedule-40 PVC,
PVC-DWV, or ABS-DWV pipe, and must not be vented in common with other gas-fired appliances. Construction through which vent/air intake pipes may be installed is
maximum 24 inches (600 mm), minimum 3/4 inches (19 mm) thickness (including roofing materials).
MINIMUM INCHES CLEARANCE TO
COMBUSTIBLE CONSTRUCTION
*
Mimimum front clearance for service 30 inches (762mm).
For installation on combustible floors only when installed on special base No. KGASB0201ALL,
Coil Assembly, Part No. CD5 or CK5, or Coil Casing, Part No. KCAKC.
Clearance in inches
This furnace is approved for
DOWNFLOWinstallation.
*
BOTTOM
0"
3"
0"
0"
TOP/PLENUM
1"
0"
30
MIN
DOWNFLOW POSITION:
SIDE
FRONT
BCK
A
SERVIE
C
FRONTSIDE
U
FRNACE
†
†
This furnace must be installed in accordance with the manufacturer's instructions and Manufactured
Home Construction and Safety Standard, Title 24 CFR, Part 3280 or, when such standard is not
applicable, the ANSI A225.1, Standard for Manufactured Home Installation (Manufactured Home Sites,
Communities and Set-Ups), or the Mobile Homes Standard CAN/CSA-Z240 MH Series-M86.
This furnace must be installed with a direct vent (combustion air and flue) system, and use a factory
accessory termination kit.
324997-201 REV. A / LIT
1. All tubing must be connected securely and routed to avoid kinks and traps.
NOTE:
COLLECTOR BOX
DRAIN TUBE
CONDENSATE TRAP
INDUCER HOUSING
DRAIN TUBE
UPPER COLLECTOR BOX
PRESSURE TUBE
COLLECTOR BOX
DRAIN TUBE
DRAIN TUBE
COUPLING
INDUCER HOUSING
DRAIN TUBE
Condensate Trap
on LEFT Side Condensate Trap
on RIGHT Side
GAS VALVE
CONDENSATE TRAP
COLLECTOR BOX EXTENSION DRAIN
TUBE
LOWER COLLECTOR BOX
PRESSURE TUBE
CAP / PLUG
DRAIN TUBES ROUTED IN
FRONT OF GAS VALVE
UPPER COLLECTOR
BOX PRESSURE TUBE
GAS VALVE
CAP / PLUG
LOWER COLLECTOR
BOX PRESSURE TUBE
BURNER ENCLOSURE
PRESSURE
REFERENCE TUBE
ASSEMBLY
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
MANUFACTURED MOBILE HOME STANDARDS
TUBE ROUTING
Furnace must be installed level, or pitched forward within 1/2 inch of level for proper drainage. Failure will result
in equipment or property damage.
FRONT
1/2" MAX
TO
LEVEL (0")
DOWNFLOW
—3—

1. Disconnect all power to the furnace. DO NOT TOUCH
THE CONTROL OR ANY WIRE CONNECTED TO THE
CONTROL PRIOR TO DISCHARGING YOUR BODY’S
ELECTROSTATIC CHARGE TO GROUND.
2. Firmly touch a clean, unpainted, metal surface of the
furnace chassis which is close to the control. Tools held in
a person’s hand during grounding will be satisfactorily
discharged.
3. After touching the chassis you may proceed to service the
control or connecting wires as long as you do nothing that
recharges your body with static electricity (for example; DO
NOT move or shuffle your feet, DO NOT touch un-
grounded objects, etc.).
4. If you touch ungrounded objects (recharge your body with
static electricity), firmly touch furnace again before touch-
ing control or wires.
5. Use this procedure for installed and uninstalled (un-
grounded) furnaces.
6. Before removing a new control from its container, dis-
charge your body’s electrostatic charge to ground to protect
the control from damage. If the control is to be installed in
a furnace, follow items 1 through 5 before bringing the
control or yourself into contact with the furnace. Put all
used AND new controls into containers before touching
ungrounded objects.
7. An ESD service kit (available from commercial sources)
may also be used to prevent ESD damage.
INTRODUCTION
The model 351DAS, Series A Furnaces are available in 3 heating
and cooling airflow sizes.
The 351DAS Condensing Gas-Fired Furnace is A.G.A./C.G.A.
design certified for installation in a manufactured (mobile) and
modular home in the downflow position and is for natural and
propane gases when installed in alcove, closets, and utility rooms.
The furnace is factory-shipped for use with natural gas and can be
converted to propane with factory-provided parts and instructions.
The design of this furnace line is NOT A.G.A./C.G.A. certified for
installation in recreation vehicles or outdoors.
These furnaces SHALL NOT be installed directly on carpeting,
tile, or any other combustible material other than wood flooring. A
factory accessory floor base MUST be used when installed on
combustible materials and wood flooring. Accessory floor base is
not required when this furnace is installed on manufacturer’s Coil
Assembly Part No. CD5 or CK5, or when Coil Box Part No.
KCAKC is used.
These furnaces are for downflow applications only.
These furnaces are shipped with the following materials to assist in
proper furnace installation. These materials are shipped in the main
blower compartment.
Loose Parts Bag includes: Quantity
Installer Packet includes: 1
Installation, Start-Up, and Operating Instructions
Service and Maintenance Instructions
User’s Information Manual
Warranty Certificate
Condensate trap 1
Gas valve adjustment tool 1
Main burner orifices (drill size No. 55) 7
Main burner orifices (drill size 1.30mm) 7
Bag for natural gas orifices 1
Vent and combustion-air pipe support 2
Combustion-air pipe perforated disk assembly 1
This furnace must be installed in accordance with the manufactur-
er’s instructions and Manufactured Home Construction and Safety
Standard, Title 24 CFR, Part 3280 or, when such standard is not
applicable, the ANSI A225.1, Standard for Manufactured Home
Installation (Manufactured Home Sites, Communities and Set-
Ups), or the Mobile Homes Standard CAN/CSA-Z240 MH Series-
M86.
Ce générateur d’air chaud doit être installé conformément avec les
instructions du fabricant et la norme intitulée Manufactured Home
Construction and Safety Standard, Title 24 CFR, Part 3280 ou,
lorsque cette norme ne s’applique pas, la norme ANSI A225.1,
intitulée Standard for Manufactured Home Installation (Manufac-
tured Home Sites, Communities and Set-Ups), ou la norme
CAN/CSA-Z240 MH Série M86 de I’ACNOR, intitulée Maisons
mobiles.
This furnace must be installed with a direct-vent (combustion air
and flue) system and a factory accessory termination kit. In a
direct-vent system, all air for combustion is taken directly from the
outside atmosphere, and all flue products are discharged to the
outside atmosphere. See furnace and factory accessory termination
kit instructions for proper installation.
Before installing the furnace in the United States, refer to the
current edition of the NFGC and the NFPA 90B. For further
information, the NFGC and the NFPA 90B are available from
National Fire Protection Association Inc., Batterymarch Park,
Quincy, MA 02269; American Gas Association, 1515 Wilson
Boulevard, Arlington, VA 22209; or from Literature Distribution.
Before installing the furnace in Canada, refer to the current edition
of the NSCNGPIC. Contact Standards Department of Canadian
Gas Association, 55 Scarsdale Road, Don Mills, Ontario, Canada
M3B 2R3.
Installations must comply with applicable regulations of serving
gas supplier and local building, heating, plumbing, or other codes
in effect in area in which installation is made. In absence of local
codes, installation must conform with NFGC.
Canadian installations must be made in accordance with NSCNG-
PIC and all authorities having jurisdiction.
These instructions cover minimum requirements for a safe instal-
lation and conform to existing national standards and safety codes.
In some instances, these instructions exceed certain local codes
and ordinances, especially those that may not have kept pace with
changing residential construction practices. We require these
instructions as a minimum for a safe installation.
CAUTION: Application of this furnace should be in-
doors with special attention given to vent sizing and
material, gas input rate, air temperature rise, unit leveling,
and unit sizing. Improper installation or misapplication of
furnace can require excessive servicing or cause prema-
ture component failure.
WARNING: Improper installation, adjustment, alter-
ation, service, maintenance, or use can cause carbon
monoxide poisoning, explosion, fire, electrical shock, or
other conditions which may cause personal injury or
property damage. Consult a qualified installer, service
agency, local gas supplier, or your distributor or branch
for information or assistance. The qualified installer or
agency must use only factory-authorized and listed kits or
accessories when modifying this product. Failure to
follow this warning could result in electrical shock, fire,
personal injury, or death.
—4—

WARNING: The conversion from natural gas to pro-
pane gas or propane gas to natural gas shall be installed
by a qualified service agency in accordance with the
manufacturer’s instructions and all applicable codes and
requirements of the authority having jurisdiction. If the
information in these instructions is not followed exactly,
a fire, explosion, or production of carbon monoxide may
result causing property damage, personal injury, or loss of
life. The qualified service agency is responsible for the
proper installation of this furnace with these instructions.
The installation is not proper and complete until the
operation of the converted appliance is checked as
specified in these manufacturer’s instructions.
AVERTISSEMENT: La conversion du gaz naturel au
gaz propane ou du gaz propane au gaz naturel doit être
effectuée par une agence de service qualifiée conformé-
ment aux instructions du fabricant et à tous les codes et à
toutes les exigences applicables de l’autorité compétente.
Si ces instructions ne sont pas observées exactement, il
peut en résulter un incendie, une explosion ou une
production d’oxyde de carbone pouvant résulter en dom-
mages matériels, lésions corporelles ou mort. L’agence de
service qualifiée est responsable d’installer correctement
cette fournaise conforément à ces instructions.
L’installation n’est ni correcte ni complète tant que le
fonctionnement de l’appareil converti n’a pas été vérifié
de la manière précisée dans ces instructions du fabricant.
For accessory installation details, refer to applicable installation
literature.
APPLICATIONS
I. GENERAL
A downflow furnace application is where furnace blower is located
above combustion and controls section of furnace, and conditioned
air is discharged downwards.
Some assembly and modifications are required for furnaces
installed in either applications shown in Fig. 4 or 5. All drain and
pressure tubes must be connected as shown in Fig. 4 or 5.
Attach adhesive pouch containing literature packet and gas con-
version parts to side of furnace for use at a later date. (See Fig. 3.)
CAUTION: When installing the air conditioning coil
casing or when servicing air conditioning, caution must
be taken to ensure furnace will not fall forward. (See Fig.
7.)
CAUTION: To prevent damage during transportation of
the home, coil casing must be secured to the floor,
furnace and coil casing must be fastened together, and
furnace must be secured to wall of the structure. When a
coil casing is not used, an accessory floor base is
required. (See furnace rating plate or clearance label for
special accessory floor base part number.) Secure floor
base to structure and attach furnace to floor base.
RECOMMENDED METHODS OF SECURING FOR TYPI-
CAL INSTALLATION. (SEE FIG. 3.) ALL MOUNTING
HARDWARE IS FIELD SUPPLIED.
1. Secure coil casing to floor.
a. Secure coil casing to floor of structure using 5/16-in. lag
screws (one each side) through lower inside flanges of
coil casing.
b. Alternate method: Attach right angle mounting brackets
or pipe strap (bent 90 degrees) to coil casing using No.
10 self tapping screws. Attach other end of
brackets/strap to floor of structure using 5/16-in. lag
screws. If coil is present in casing, be careful not to
damage condensate pan with tip of screw or remove coil
from casing.
2. Fasten furnace to coil casing.
a. Secure furnace to coil casing using 2 No. 10 self tapping
screws (one on each side of burner enclosure) through
cell panel flange, lower furnace casing plate, and coil
casing top flange.
b. Alternate method: Attach pipe strap to both furnace
casing and coil casing (one each side). If coil is present
in coil casing, be careful not to damage it with tip of
screw.
1. Secure furnace to structure.
a. Attach pipe strap to top of furnace casing using No. 10
self tapping screws. Angle strap down and away from
back of furnace, remove all slack, and fasten to wall stud
of structure using 5/16-in. lag screws. Typical both sides
of furnace.
b. Alternate method: Secure furnace to wall stud using
1/8-in. thick right-angle brackets. Attach brackets to
furnace using No. 10 self tapping screws, and to wall
stud using 5/16-in. lag screws.
WHEN COIL CASING IS NOT INSTALLED (NOT SHOWN)
1. Accessory floor base MUST be used. Review floor base
Installation Instructions before installation.
2. Secure accessory floor base to structure using 5/16-in. lag
screws.
3. Fasten furnace to accessory floor base using No. 10 self
tapping screws through tabs on both sides of base (two each
side).
II. CONDENSATE TRAP INSTALLATION
1. Select condensate trap location from 1 shown in either Fig.
4or5.
2. If casing hole filler cap is installed in casing hole selected
for trap location, remove cap and install it in unused trap
location hole.
3. Install condensate trap (located in factory-supplied loose
parts bag) into selected location casing hole by inserting
tabs at top of trap onto upper edge of hole and rotating trap
until lower tabs fit into hole. Then allow trap to slide down
slightly and lock into position. (See Fig. 6.)
4. Connect collector box drain tube to condensate trap.
NOTE: See Fig. 4, 5, or tube routing label on main furnace door
to check for proper tube connections.
a. Condensate trap located on left-hand side of casing. (See
Fig. 4.)
(1.) Remove smooth collector box extension tube and
coupling from corrugated collector box tube and
discard.
(2.) Connect corrugated collector box tube to conden-
sate trap.
—5—

(3.) Clamp tube to prevent any condensate leakage.
b. Condensate trap located on right-hand side of casing.
(See Fig. 5.)
(1.) Cut smooth collector box extension tube as shown
in Table 1 for model furnace used.
(2.) Connect collector box drain tube and extension tube
to condensate trap.
(3.) Clamp tube to prevent any condensate leakage.
5. Connect inducer housing drain tube to condensate trap. (See
Fig. 4 or 5.)
a. Cut smooth inducer housing drain tube as shown in
Table 1 for model furnace used.
b. Connect inducer housing drain tube to condensate trap.
c. Clamp tube to prevent any condensate leakage.
1. Connect collector box upper pressure tube to condensate
trap. (See Fig. 4 or 5.)
a. Cut collector box upper pressure tube as shown in Table
1 for model furnace used.
b. Connect collector box upper pressure tube to condensate
trap.
c. Clamp tube to prevent any condensate leakage.
2. Refer to Condensate Drain section for recommendations
and procedures for installing field drain tubing.
Fig. 3—Securing Furnace to Structure A99016
SECURE COIL CASING TO FLOOR
LAG SCREWS THROUGH COIL CASING
FLANGE (TYPICAL BOTH SIDES)
WALL STUDS
ATTACH
ADHESIVE
POUCH TO
DOOR OR
SIDE
RETURN AIR PLENUM
(WHEN USED)
ANGLE BRACKET OR PIPE STRAP
LITERATURE
AND
EXTRA
PARTS
BAG
LITERATURE
AND
EXTRA
PARTS
BAG
PIPE STRAP REMOVE SLACK
(TYPICAL BOTH SIDES)
1/8-IN. THICK ANGLE MOUNTING
BRACKET (TYPICAL BOTH SIDES)
SECURE FURNACE TO STRUCTURE
OR
SCREWS THROUGH CASING FLANGES
PIPE STRAP FASTENED TO FURNACE
AND COIL CASING SIDES
(TYPICAL BOTH SIDES)
FASTEN FURNACE TO CASING
OR
NOTE: USE 5/16-IN. LAG SCREWS WHEN SECURING
TO STRUCTURE WALLS AND FLOOR. USE NO. 10
SELF TAPPING SCREWS WHEN FASTENING TO
SHEET METAL.
OR
COIL
CASING
FURNACE
1" MAXIMUM
4"
MAX
—6—

Fig. 4—Downflow Tube Configuration
(Left-Hand Trap Installation)
A99042
COLLECTOR BOX
LOWER PRESSURE
TUBE
COLLECTOR BOX
UPPER PRESSURE
TUBE
COLLECTOR BOX
DRAIN TUBE
CONDENSATE
TRAP
INDUCER HOUSING
DRAIN TUBE
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
CAP
PLUG OR CAP
Fig. 5—Downflow Tube Configuration
(Right-Hand Trap Installation)
A99043
LOWER
COLLECTOR BOX
PRESSURE TUBE
UPPER
COLLECTOR BOX
PRESSURE TUBE
COLLECTOR BOX
DRAIN TUBE
COLLECTOR BOX
EXTENSION
DRAIN TUBE
CONDENSATE
TRAP
INDUCER HOUSING
DRAIN TUBE
DRAIN TUBE
COUPLING
CAP
PLUG OR CAP
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
Fig. 6—Condensate Trap A98648
1⁄2OD
INDUCER HOUSING
DRAIN CONNECTION
1⁄4OD
COLLECTOR BOX TO
TRAP RELIEF PORT
5⁄8OD
COLLECTOR BOX
DRAIN CONNECTION
1⁄2-IN. PVC OR CPVC
SCREW HOLES FOR
DOWNFLOW (OPTIONAL)
14
2
78
18
7
WIRE TIE
GUIDES
(WHEN USED)
12
1
34
1
34
FRONT VIEW SIDE VIEW
FURNACE
DOOR CONDENSATE
TRAP
78
14
26
4
FURNACE
SIDE
12
1
SIDE VIEW FRONT VIEW
(SHOWN ON RIGHT-HAND SIDE. MAY
BE INSTALLED ON LEFT-HAND SIDE.)
FIELD
DRAIN
CONN
TABLE 1—CONDENSATE TRAP TUBING LENGTH (IN.)
TUBING MUST NOT KINK OR SAG
Trim and route tubing to prevent kinking or sagging. Clamp drain tubes to prevent leakage.
TUBE FACTORY-SUPPLIED
LENGTH 036080 AND 048080 060080
Left-Side Trap* Right-Side Trap* Left-Side Trap* Right-Side Trap*
Collector Box Exten-
sion Drain Tube 17 0 (Remove extension tube and coupling.) 11 (6) 0 (Remove extension tube and coupling.) 12 (5)
Inducer Tube 20 9 (11) 18 (2) 9 (11) 20 (0)
Upper Collector Box
Pressure Tube 26 26 (0) 19 (7) 26 (0) 19 (7)
*Trim tube to this length. (Length to trim off.)
—7—

3. Refer to Condensate Drain Protection section for recom-
mendations and procedures when condensate trap maybe
exposed to freezing temperatures.
LOCATION
I. GENERAL
Return-air plenum is not required when this direct vent furnace is
installed in a dedicated confined space or installed in a space with
other direct vent appliances. (Manufactured Home Construction
and Safety Standards, Title 24 CFR, Part 3280.709.e.1).
When the furnace is installed in a space containing other non-
direct vent appliances, the return air must be handled by ducts and
sealed to furnace casing. The ducts terminate outside the space
containing the furnace to ensure there will not be a negative
pressure condition within equipment room or space. Furnace may
be located in a confined space without special provisions for
dilution or ventilation air. This furnace must be installed so
electrical components are protected from water.
Locate furnace as close to center of air distribution system as
possible.
Locate furnace so combustion-air and vent pipe maximum lengths
are not exceeded. Refer to Table 7.
Fig. 7—Furnace Support for Servicing Air
Conditioning Coil
A99007
FURNACE
FIELD-SUPPLIED
SUPPORTS
(1 X 4 OR 2 X 4
3 PLACES)
NOTE: For proper furnace operation, install furnace so that it is
level or pitched forward within 1/2 in. to ensure proper condensate
drainage from secondary heat exchangers.
A99019
FRONT
LEVEL (0″)
TO
1⁄2″MAX
NOTE: These furnaces are designed for a minimum continuous
return-air temperature of 60°F or intermittent operation down to 55°F
such as when used with a night setback thermostat. Return-air
temperature must not exceed a maximum of 85°F. Failure to follow
these return-air temperature limits may affect reliability of heat
exchangers, motors, and controls.
A99020
FRONT
RETURN AIR
MAX 85°F MIN 55°F
°F°F
—8—

CAUTION: If these furnaces are used during construc-
tion when adhesives, sealers, and/or new carpets are
being installed, make sure all combustion and circulating
air requirements are followed. If operation of furnace is
required during construction, use clean outside air for
combustion and ventilation. Compounds of chlorine and
fluorine, when burned with combustion air, form acids
which will cause corrosion of heat exchangers. Some of
these compounds are found in paneling, dry wall adhe-
sives, paints, thinners, masonry cleaning materials, and
many other solvents commonly used in construction
process.
Excessive exposure to contaminated combustion air will
result in safety and performance related problems.
Provide ample space for servicing and cleaning. Always comply
with minimum fire protection clearances shown on unit’s clear-
ance to combustibles label. (See Fig. 2.) Locate furnace where
available electric power and gas supplies meet specifications on
furnace rating plate.
II. FURNACE LOCATION RELATIVE TO COOLING
EQUIPMENT
The cooling coil must be installed parallel with or on downstream
side of furnace to avoid condensation in heat exchanger. When
installed parallel with a furnace, dampers or other means used to
control flow of air must prevent chilled air from entering furnace.
If dampers are manually operated, they must be equipped with a
means to prevent operation of either unit unless damper is in
full-heat or full-cool position.
III. HAZARDOUS LOCATIONS
INSTALLATION
I. INSTALLATION IN DOWNFLOW APPLICATION
NOTE: For downflow application, this furnace is approved for
use on combustible flooring when accessory floor base (available
from manufacturer) Part No. KGASB0201ALL is used. Accessory
floor base is not required when this furnace is installed on
manufacturer’s Coil Assembly Part No. CD5 or CK5, or Coil Box
Part No. KCAKC is used.
1. Determine application of condensate trap being installed
from Table 1.
2. Construct hole in floor per dimensions specified in Table 2
and Fig. 8.
3. Construct plenum to dimensions specified in Table 2 and
Fig. 8.
4. If downflow accessory floor base (KGASB) is used, install
as shown in Fig. 9.
If Coil Assembly Part No. CD5 or CK5 or Coil Box Part
No. KCAKC is used, install as shown in Fig. 10.
NOTE: Remove furnace perforated, discharge duct flanges when
they interfere with mating flanges on coil on downflow subbase.
To remove furnace perforated, discharge duct flange, use wide
duct pliers or duct flange tool to bend flange back and forth until
it breaks off. Be careful of sharp edges. (See Fig. 11.)
WARNING: Do not install furnace on its back. Safety
control operation will be adversely affected. Never con-
nect return-air ducts to back of furnace. Failure to follow
this warning could result in fire, personal injury, or death.
A93043
FRONT
BACK
FRONT
B
A
C
K
CAUTION: If these furnaces are installed in an uncon-
ditioned space where ambient temperatures may be 32°F
or lower, freeze protection measures must be taken.
A93058
32°F MINIMUM INSTALLED
AMBIENT OR FREEZE
PROTECTION REQUIRED
WARNING: When furnace is installed in a residential
garage, it must be installed so that burners and ignition
sources are located a minimum of 18 in. above floor. The
furnace must be located or protected to avoid physical
damage by vehicles. When furnace is installed in a public
garage, airplane hangar, or other building having a
hazardous atmosphere, unit must be installed in accor-
dance with requirements of National Fire Protection
Association, Inc.
A93044
18-IN. MINIMUM
TO BURNERS
—9—

TABLE 2—OPENING DIMENSIONS (IN.)
FURNACE
CASING
WIDTH APPLICATION PLENUM OPENING FLOOR OPENING
ABCD
17-1/2
Downflow Applications on Non-Combustible Flooring 15-7/8 19 16-1/2 19-5/8
Downflow Applications on Combustible Flooring Using KGASB Subbase
Furnace with or without CD5 or CK5 Coil Assembly or KCAKC Coil Box 15-1/8 19 16-3/4 20-3/8
Downflow Applications on Combustible Flooring NOT Using KGASB Subbase
Furnace with CD5 or CK5 Coil Assembly or KCAKC Coil Box 15-1/2 19 16-1/2 20
21
Downflow Applications on Non-Combustible Flooring 19-3/8 19 20 19-5/8
Downflow Applications on Combustible Flooring Using KGASB Subbase
Furnace with or without CD5 or CK5 Coil Assembly or KCAKC Coil Box 18-5/8 19 20-1/4 20-3/8
Downflow Applications on Combustible Flooring NOT Using KGASB Subbase
Furnace with CD5 or CK5 Coil Assembly or KCAKC Coil Box 19 19 20 20
Fig. 9—Furnace, Plenum, and Subbase
Installed on a Combustible Floor
A96285
DOWNFLOW
SUBBASE
SHEET METAL
PLENUM
FLOOR
OPENING
FURNACE
(OR COIL CASING
WHEN USED)
COMBUSTIBLE
FLOORING
Fig. 8—Floor and Plenum Opening Dimensions
A96283
PLENUM
OPENING
C
A
BD
FLOOR
OPENING
Fig. 10—Furnace, Plenum, and Coil
Assembly or Coil Box Installed
on a Combustible Floor
A96284
CD5 OR CK5
COIL ASSEMBLY
OR KCAKC
COIL BOX
FURNACE
SHEET METAL
PLENUM
FLOOR
OPENING
COMBUSTIBLE
FLOORING
—10—

WARNING: Do not bend duct flanges inward as shown.
This will affect airflow across heat exchangers and may
cause limit cycling or premature heat exchanger failure.
Remove duct flange completely or bend it inward a
minimum of 210° as shown.
II. FILTER ARRANGEMENT
CAUTION: Never operate unit without a filter or with
blower access panel removed.
Factory-supplied washable framed filter is shipped in blower
compartment. Determine location for filter and relocate filter
retaining wire if necessary. See Table 3 to determine correct filter
size for desired filter location. Table 3 indicates filter size,
location, and quantity shipped with this furnace. See Fig. 1 for
location and size of top return-air opening.
III. GAS PIPING
Gas piping must be installed in accordance with national and local
codes. Refer to current edition of NFGC. Canadian installations
must be made in accordance with NSCNGPIC and all authorities
having jurisdiction. Gas supply line should be a separate line
running directly from meter to furnace, if possible. Refer to Table
4 for recommended gas pipe sizing. Risers must be used to connect
to furnace and to meter. Support all gas piping with appropriate
straps, hangers, etc. Use a minimum of 1 hanger every 6 ft. Joint
compound (pipe dope) should be applied sparingly and only to
male threads of joints. Pipe dope must be resistant to propane gas.
CAUTION: Connect gas pipe to furnace using a backup
wrench to avoid damaging gas controls.
WARNING: Gas valve shutoff switch MUST be facing
forward or tilted upward. Failure to follow this warning
could result in property damage or death.
Fig. 11—Duct Flanges
A93029
NO
YES
YES
PERFORATED
DISCHARGE DUCT
FLANGE
210°
MIN
TABLE 3—FILTER INFORMATION
FURNACE
CASING
WIDTH (IN.)
FILTER SIZE (IN.) FILTER TYPE
FRAMED
Top Return
17-1/2 (1) 16 X 25 X 1* Cleanable
21 (1) 20 X 25 X 1* Cleanable
* Factory-provided with furnace.
Fig. 12—Filter Arrangement A99021
WASHABLE
FILTER
FILTER
SUPPORT
FILTER
RETAINER
171⁄2-IN. WIDE 
CASINGS ONLY:
INSTALL FIELD-SUPPLIED
FILTER FILLER STRIP
UNDER FILTER.
1″
24 1/2″
3″
TABLE 4—MAXIMUM CAPACITY OF PIPE*
NOMINAL
IRON
PIPE
SIZE
(IN.)
INTERNAL
DIAMETER
(IN.)
LENGTH OF PIPE (FT)
10 20 30 40 50
1/2 0.622 175 120 97 82 73
3/4 0.824 360 250 200 170 151
11.049 680 465 375 320 285
1-1/4 1.380 1400 950 770 660 580
1-1/2 1.610 2100 1460 1180 990 900
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14-in. wc) or less, and
a pressure drop of 0.5-in. wc (based on a 0.60 specific gravity gas).
Ref: Table 10-2 NFPA 54-1996.
—11—

WARNING: Never purge a gas line into a combustion
chamber. Never use matches, candles, flame, or other
sources of ignition for purpose of checking leakage. Use
a soap-and-water solution to check for leakage. A failure
to follow this warning could result in fire, explosion,
personal injury, or death.
WARNING: Use proper length of pipe to avoid stress on
gas control manifold. Failure to follow this warning could
result in a gas leak resulting in fire, explosion, personal
injury, or death.
Install a sediment trap in riser leading to furnace. Trap can be
installed by connecting a tee to riser leading to furnace so
straight-through section of tee is horizontal. Then connect a capped
nipple into lower end of tee. Capped nipple should extend below
level of gas controls. Place a ground joint union between gas
control manifold and manual gas shutoff valve. (See Fig. 13.)
CAUTION: If a flexible connector is required or al-
lowed by authority having jurisdiction, black iron pipe
shall be installed at gas valve and extend a minimum of
2 in. outside furnace casing.
An accessible manual shutoff valve MUST be installed upstream
of furnace gas controls and within 6 ft of furnace. A 1/8-in. NPT
plugged tapping, accessible for test gage connection, MUST be
installed immediately upstream of gas supply connection to
furnace and downstream of manual shutoff valve.
NOTE: The gas valve inlet press tap connection is suitable to use
as test gage connection providing test pressure DOES NOT exceed
maximum 0.5 psig (14-in. wc) stated on gas valve. (See Fig. 31.)
Piping should be pressure tested in accordance with local and
national plumbing and gas codes before furnace is attached. In
Canada, refer to current edition of NSCNGPIC. If pressure
exceeds 0.5 psig (14-in. wc), gas supply pipe must be disconnected
from furnace and capped before pressure test. If test pressure is
equal to or less than 0.5 psig (14-in. wc), turn off electric shutoff
switch located on gas valve before test. It is recommended that
ground joint union be loosened before pressure testing. After all
connections have been made, purge lines and check for leakage.
ELECTRICAL CONNECTIONS
See Fig. 14 for field wiring diagram showing typical field 115-v
and 24-v wiring. Check all factory and field electrical connections
for tightness.
WARNING: Blower access panel door switch opens
115-v power to control center. No component operation
can occur. Do not bypass or close switch with panel
removed. Failure to follow this warning could result in
personal injury or death.
CAUTION: Furnace control must be grounded for
proper operation or control will lock out. Control is
grounded through green wire routed to gas valve and
burner box screw.
I. 115-V WIRING
Before proceeding with electrical connections, make certain that
voltage, frequency, and phase correspond to that specified on unit
rating plate. Also, check to be sure that service provided by utility
is sufficient to handle load imposed by this equipment. Refer to
rating plate or Table 5 for equipment electrical specifications.
Make all electrical connections in accordance with National
Electrical Code (NEC) ANSI/NFPA 70-1999 and any local codes
or ordinances that might apply. For Canadian installations, all
electrical connections must be made in accordance with Canadian
Electrical Code CSA C22.1 or subauthorities having jurisdiction.
Use a separate, fused branch electrical circuit containing a properly
sized fuse or circuit breaker for this furnace. See Table 5 for wire
size and fuse specifications. An electric disconnect switch must be
located within sight from and readily accessible to furnace.
NOTE: Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, control center LED status indicator light will
flash rapidly and furnace will NOT operate.
WARNING: The cabinet MUST have an uninterrupted
or unbroken ground according to NEC ANSI/NFPA
70-1999 and Canadian Electrical Code CSA C22.1 or
local codes to minimize personal injury if an electrical
fault should occur. This may consist of electrical wire or
conduit approved for electrical ground when installed in
accordance with existing electrical codes. Do not use gas
piping as an electrical ground. Failure to follow this
warning could result in electrical shock, fire, or death.
Fig. 13—Typical Gas Pipe Arrangement A99022
UNION
SEDIMENT
TRAP
MANUAL
SHUTOFF
VALVE
(REQUIRED)
GAS
SUPPLY
FRONT
CAUTION: Do not connect aluminum wire between
disconnect switch and furnace. Use only copper wire.
A93033
COPPER
WIRE ONLY
ELECTRIC
DISCONNECT
SWITCH
ALUMINUM
WIRE
—12—

J-BOX RELOCATION
1. Remove 2 screws holding auxiliary J-box. (See Fig. 15.)
2. Rotate J-box 180° and attach box to left side, using holes
provided.
CAUTION: If manual disconnect switch is to be
mounted on furnace, select a location where a drill or
fastener will not contact electrical or gas components.
II. 24-V WIRING
Make field 24-v thermostat connections at 24-v terminal block on
control center. For proper cooling operation, Y wire from thermo-
stat MUST be connected to Y terminal on control center, as shown
in Fig. 14. The 24-v terminal board is marked for easy connection
of field wiring. (See Fig. 16.) The 24-v circuit contains a 3-amp,
automotive-type fuse located on control center. (See Fig. 17.) Any
electrical shorts of 24-v wiring during installation, service, or
maintenance may cause fuse to blow. If fuse replacement is
required, use only a fuse of identical size (3 amp).
NOTE: Use AWG No. 18 color-coded copper thermostat wire for
lengths up to 100 ft. For wire lengths over 100 ft, use AWG No.
16 wire.
III. ACCESSORIES
1. Electronic Air Cleaner (EAC)
Two quick-connect terminals marked EAC-1 and EAC-2,
are provided for EAC connection. (See Fig. 17.) These
terminals are energized with 115v (1.5-amp maximum)
during blower motor operation.
2. Humidifier (HUM)
A quick-connect terminal (HUM) and screw terminal (COM)
are provided for 24-v humidifier connection. (See Fig. 16.)
HUM terminal is energized with 24v (0.5-amp maximum)
after inducer motor prepurge period.
NOTE: A field-supplied, 115-v controlled relay connected to
EAC terminals may be added if humidifier operation is desired
during blower operation.
DIRECT VENTING
The 351DAS Furnace requires a dedicated direct-vent system. In a
direct-vent system, all air for combustion is taken directly from
outside atmosphere, and all flue products are discharged to outside
atmosphere.
I. REMOVAL OF EXISTING FURNACES FROM
COMMON VENT SYSTEMS
If furnace being replaced was connected to a common vent system
with other appliances, the following steps shall be followed with
each appliance connected to the venting system placed in opera-
tion, while any other appliances connected to the venting system
are not in operation:
1. Seal any unused openings in the venting system.
Fig. 14—Heating and Cooling Application Wiring Diagram A98209
115-V
FIELD-SUPPLIED
DISCONNECT
AUXILIARY
J-BOX
CONTROL
BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-
ONLY
FIVE
WIRE
NOTE 1
NOTE 2 FIELD-SUPPLIED
DISCONNECT
CONDENSING
UNIT
TWO
WIRE
FURNACE
R
G
C
WCR GY
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
WHT
BLK
WHT
BLK
NOTES: Connect Y-terminal as shown for proper operation.
Some thermostats require a "C" terminal connection as shown.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
W
Y
GND
THERMOSTAT
TERMINALS
1.
2.
3.
Fig. 15—Relocating J-Box A99023
ALTERNATE
FIELD
LOCATION
FACTORY
INSTALLED
LOCATION
—13—

Fig. 16—Wiring Diagram A99041e
PCB
BLOWER OFF DELAY
SELECTION CHART
90 SEC 135 SEC 180 SEC 225 SEC
GVR
HI/LO
RELAY
SEC-1 SEC-2
WHT
PL1 321
654
987
LED
TEST/TWIN
BLOWER
OFF
DELAY
G R Y
W C
HUM
HSIR IDR BLWR
BLOWER
SPEED
SELECT
FU1
COOL
HEAT
L2
PL3
PL2
VAC
120
L1 PR1 1
2
1 2 3PR2
24 VAC-3A
FUSE
SPARE-2
SPARE-1
EAC-1 EAC-2
C
1.5 AMP
12
PL5 WHT BRN
GRN
BLK
IDM
BRN
CAP -2
WHT
WHT
BLK
BLK
HSI
AUX
OL
M
BLK
WHT
WHT (COM)
RED (LO)
BLU (MED LO)
NOTE #8
OL
START
BLWM
YEL (MED HI)
BLK (HI)
BRN
BRN
TRAN
BLU
RED
BLK
WHT
WHT (COM)
GRN
CAP -1
GRN 2-C
RED
FSE
NOTE #5
1-M 3-P
GV
FRS
BLU YEL
RED
NOTE #6
LS
RED
ORN
PRS (WHEN USED)
LGPS
FUSED DISCONNECT
SWITCH (WHEN REQ'D)
NOTE #4
WHT
GRN
GRN
JB
LEGEND
BLWR BLOWER MOTOR RELAY, SPST-(N.O.) BLWM BLOWER MOTOR CAP CAPACITOR CPU MICROPROCESSOR AND CIRCUITRY EAC-1 ELECTRONIC AIR CLEANER CONNECTION (115 VAC 1.5 AMP MAX.) EAC-2 ELECTRONIC AIR CLEANER CONNECTION (COMMON) FRS FLAME ROLLOUT SW. -MANUAL RESET, SPST-(N.C.) FSE FLAME PROVING ELECTRODE FU1 FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE, FACTORY INSTALLED FU2 FUSE OR CIRCUIT BREAKER CURRENT INTERRUPT DEVICE
(FIELD INSTALLED & SUPPLIED)
GND EQUIPMENT GROUND GV GAS VALVE-REDUNDANT OPERATORS GVR GAS VALVE RELAY, DPST-(N.O.) HI/LO BLOWER MOTOR SPEED CHANGE RELAY, SPDT HSI HOT SURFACE IGNITOR (115 VAC) HSIR HOT SURFACE IGNITOR RELAY, SPST-(N.O.) HUM 24VAC HUMIDIFIER CONNECTION (.5 AMP. MAX.) IDM INDUCED DRAFT MOTOR IDR INDUCED DRAFT RELAY, SPST-(N.O.) ILK BLOWERACCESS PANEL INTERLOCK SWITCH, SPST-(N.O.) JB JUNCTION BOX LED LIGHT-EMITTING DIODE FOR STATUS CODES LGPS LOW GAS PRESSURE SWITCH, SPST-(N.O.) LS LIMIT SWITCH, AUTO RESET, SPST(N.C.) OL AUTO-RESET INTERNAL MOTOR OVERLOAD TEMP. SW. PCB PRINTED CIRCUIT BOARD
PL1 9-CIRCUIT CONNECTOR PL2 2-CIRCUIT PCB CONNECTOR PL3 3-CIRCUIT IDM CONNECTOR PL4 3-CIRCUIT IDM EXTENSION CONNECTOR PL5 2-CIRCUIT HSI/PCB CONNECTOR PRS PRESSURE SWITCH, SPST-(N.O.) SW1 & 2 BLOWER OFF DELAY TEST/TWIN COMPONENT TEST & TWIN TERMINAL TRAN TRANSFORMER-115VAC/24VAC
JUNCTION UNMARKED TERMINAL PCB TERMINAL FACTORY WIRING (115VAC) FACTORY WIRING (24VAC) FIELD WIRING (115VAC) FIELD WIRING (24VAC) CONDUCTOR ON PCB FIELD WIRING TERMINAL FIELD EARTH GROUND EQUIPMENT GROUND FIELD SPLICE PLUG RECEPTACLE
L1
L1
BLWR
HI/LO
TO 115VAC FIELD DISCONNECT
NOTE #4
EQUIPMENT GROUND
SPARE-1
HEAT
SPARE-2
COOL NOTE #8
COM
HSIR EAC-1
START
OL
COM
HI
MED HI
MED LO
LO
BLWM
SCHEMATIC DIAGRAM
(NATURAL GAS & PROPANE)
EAC-2
11HSI
2
PL52
PL2
3PL3
PR2
115VAC
PR1
TRAN 24VAC
1
2
BRN
M
IDR
TEST/TWIN
FU1 NOTE #7
IDM
OL
AUX
BRN
CAP -2
CAP-1
L2
FRS LS
LGPS (WHEN USED)
NOTE #6
PL1 PRS
GV
2-C
1-M
3-P
NOTE #5
8
FSE
9
6 5
CPU
HSIR IDR BLWR
Y G
C
R W
GVR-2
SEC-1
HI/LO GVR
GVR-1
SEC-2
NOTES:
322854-101 REV. D (LIT)
1. IF ANYOF THEORIGINAL EQUIPMENT WIRE IS REPLACED USE WIRE RATED FOR 105˚C. 2. INDUCER (IDM) AND BLOWER (BLWM) MOTORS CONTAIN INTERNAL
AUTO-RESET THERMAL OVERLOAD SWITCHES (OL).
3. BLOWER MOTOR SPEEDSELECTIONSARE FOR AVERAGE CONDITIONS, SEE INSTALLATION
INSTRUCTIONS FOR DETAILS ON OPTIMUM SPEED SELECTION.
4. USE ONLY COPPER WIRE BETWEEN THE DISCONNECT SWITCH AND THE
FURNACE JUNCTION BOX (JB).
5. THIS WIRE MUST BE CONNECTED TO FURNACE SHEETMETAL FOR CONTROL TO PROVE
FLAME.
6. FACTORY CONNECTED WHEN LGPS NOT USED. 7. REPLACE ONLY WITH A 3 AMP FUSE. 8. YELLOW LEAD NOT ON ALL MOTORS. 9. BLOWER-ON DELAY, GAS HEATING 60 SECONDS, COOLING OR HEAT PUMP 2 SECONDS. 10. BLOWER-OFF DELAY, GAS HEATING90, 135, 180 OR 225 SECONDS, COOLINGOR
HEAT PUMP 90 SECONDS. (135 SECONDS ONLY ON SOME MODELS)
11. IGNITION-LOCKOUT WILL OCCUR AFTER FOUR CONSECUTIVE UNSUCCESSFUL
TRIALS-FOR-IGNITION. CONTROL WILL AUTO-RESET AFTER THREE HOURS.
12. SOME MODELS MAY HAVE SPADE QUICK CONNECT TERMINALS.
BLK
OM
SW2
SW1
OM
2 3
4 7
1
OM
HUM
123
WHT
BLK
GRN
PL4
PL4
2
3
1
NEUTRAL
NEUTRAL
WHT
ILK
FU2
BLK
L1
ILK
(NOT ONALL MODELS)
SEE NOTE #10
NOTE #12
GND
GND
—14—

2. Inspect the venting system for proper size and horizontal
pitch as required in the National Fuel Gas Code, ANSI
Z223.1 or the CAN/CGA B149 Installation Codes and these
instructions. Determine that there is no blockage or restric-
tion, leakage, corrosion, and other deficiencies which could
cause an unsafe condition.
3. In so far as is practical, close all building doors and
windows and all doors between the space in which the
appliance(s) connected to the venting system are located
and other spaces of the building. Turn on clothes dryers and
any appliance not connected to the venting system. Turn on
any exhaust fans, such as range hoods and bathroom
exhausts, so they shall operate at maximum speed. Do not
operate a summer exhaust fan. Close fireplace dampers.
4. Follow the lighting instructions. Place the appliance being
inspected in operation. Adjust thermostat so appliance shall
operate continuously.
5. Test for draft hood equipped appliance spillage at the draft
hood relief opening after 5 minutes of main burner opera-
tion. Use the flame of a match or candle.
6. After it has been determined that each appliance connected
to the venting system properly vents when tested as outlined
above, return doors, windows, exhaust fans, fireplace damp-
ers, and any other gas-burning appliance to their previous
conditions of use.
7. If improper venting is observed during any of above tests,
the venting system must be corrected.
Vent system or vent connectors may need to be resized. For any
other appliances when resizing vent systems or vent connectors,
system or connector must be sized to approach minimum size as
determined using appropriate table found in the NFGC or NSC-
NGPIC.
II. COMBUSTION-AIR AND VENT PIPING
A. General
Combustion-air and vent pipe fittings must conform to American
National Standards Institute (ANSI) standards and American
Society for Testing and Materials (ASTM) standards D1785
(schedule-40 PVC), D2665 (PVC-DWV), D2241 (SDR-21 and
SDR-26 PVC), D2661 (ABS-DWV), F628 (schedule-40 ABS), or
F891 (PVC-DWV cellular core). Pipe cement and primer must
conform to ASTM standards D2564 (PVC) or D2235 (ABS). See
Table 7 for maximum pipe lengths and Fig. 22, 23, 24, 25, and 26
for exterior piping arrangements.
In Canada construct all combustion-air and vent pipes for this unit
of CSA or ULC certified schedule-40 PVC, PVC-DWV or
ABS-DWV pipe and pipe cement. SDR pipe is NOT approved in
Canada.
TABLE 5—ELECTRICAL DATA
UNIT
SIZE
VOLTS—
HERTZ—
PHASE
OPERATING
VOLTAGE RANGE MAX
UNIT
AMPS
UNIT
AMPACITY†
MIN
WIRE
SIZE
MAX WIRE
LENGTH
(FT)‡
MAX FUSE
OR CKT BKR
AMPS**
Max* Min*
036080 115—60—1 127 104 7.6 10.4 14 36 15
048080 115—60—1 127 104 10.0 13.4 14 28 15
060080 115—60—1 127 104 14.1 18.4 12 31 20
* Permissible limits of voltage range at which unit will operate satisfactorily.
† Unit ampacity = 125 percent of largest operating component’s full load amps plus 100 percent of all other potential operating components’ (EAC, humidifier, etc.) full load
amps.
‡ Length shown is as measured 1 way along wire path between unit and service panel for maximum 2 percent voltage drop.
** Time-delay type is recommended.
Fig. 17—Control Center A95086
C
OM

24V

HUM
GRYW
3-AMP FUSE
HUMIDIFIER TERMINAL
(24-VAC 0.5 AMP MAX)
LED OPERATION &
DIAGNOSTIC LIGHT
HARNESS CONNECTOR
24-V TRANSFORMER SEC-2
SPARE-1
SPARE-2
EAC-1
EAC-ELECTRONIC AIR CLEANER
TERMINALS (115-VAC 1.5 AMP MAX)
EAC-2
115-VAC (L2) NEUTRAL
CONNECTION
24-V THERMOSTAT
TERMINALS
BLOWER SPEED
SELECTION TERMINALS
INDUCER MOTOR
CONNECTOR
115-VAC (L1)
POWER SUPPLY
HOT SURFACE
IGNITOR CONNECTOR
HEAT
COOL
SEC-1
TEST/TWIN
—15—

NOTE: Furnace combustion-air and vent pipe connections are
sized for 2-in. pipe. Any pipe size change should be made outside
furnace casing in vertical pipe. (See Fig. 18.) This allows proper
drainage of vent condensate.
Combustion-air and vent pipes must terminate together in same
atmosphere pressure zone, either through roof or sidewall (roof
termination preferred), using accessory termination kit. See Table
6 for required clearances.
Furnace combustion-air and vent pipe connections must be at-
tached as shown in Fig. 19. Combustion-air intake plug fitting and
inducer housing alternate vent cap may need to be relocated in
some applications.
NOTE: Slope combustion-air and vent pipes a minimum of 1/4
in. per linear ft with no sags between hangers.
CAUTION: When combustion-air pipe is installed
above a suspended ceiling, pipe must be insulated with
3/8-in. thick Armaflex-type insulation. Combustion-air
pipe should also be insulated when it passes through
warm, humid space.
CAUTION: When vent pipe is exposed to temperatures
below freezing, such as when it passes through an
unheated space or when a chimney is used as a raceway,
pipe must be insulated as shown in Table 8 with
Armaflex-type insulation.
CAUTION: Combustion air must not be taken from
inside structure because inside air is frequently contami-
nated by halogens, which include fluorides, chlorides,
bromides, and iodides. These elements are found in
aerosols, detergents, bleaches, cleaning solvents, salts, air
fresheners, adhesives, paint, and other household prod-
ucts. Locate combustion-air inlet as far as possible from
swimming pool and swimming pool pump house.
Excessive exposure to contaminated combustion air will
result in safety and performance related problems.
WARNING: Solvent cements are combustible. Keep
away from heat, sparks, and open flame. Use only in
well-ventilated areas. Avoid breathing in vapor or allow-
ing contact with skin or eyes. Failure to follow this
warning could result in fire, property damage, personal
injury, or death.
WARNING: All combustion-air and vent pipes must be
airtight and watertight. Pipes must also terminate exactly
as shown in Fig. 22, 23, 24, 25, or 26. Failure to follow
this warning could result in property damage, personal
injury, or death.
NOTE: The minimum combustion-air and vent pipe length (each)
for these furnaces is 5 ft. Short pipe lengths (5-8 ft) may discharge
water droplets. These droplets may be undesirable, and a 12-in.
minimum offset pipe section is recommended, as shown in Fig. 20,
to reduce excessive droplets from exiting vent pipe outlet.
B. Combustion-Air and Vent Pipe Diameter
Determine combustion-air and vent pipe diameter.
1. Using Table 7, individually determine the combustion-air
and vent pipe diameters. Pick the larger of these 2 pipe
diameters and use this diameter for both combustion-air and
vent pipes.
Fig. 18—Combustion-Air and Vent Pipe Diameter
Transition Location and Elbow Configuration
A93034
FURNACE
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
NOT IN
HORIZONTAL
SECTION
TABLE 6—COMBUSTION-AIR AND VENT PIPE
TERMINATION CLEARANCES
LOCATION CLEARANCE (FT)
U.S.A. Canada
Above grade level or above antici-
pated snow depth 11†
Dryer vent 33
From plumbing vent stack 33
From any mechanical fresh air intake 16
For furnaces with an input capacity
less than 100,000 Btuh—from any non-
mechanical air supply (windows or
doors which can be opened) or
combustion-air opening
11
From service regulator vent, electric
and gas meters, and relief equipment 4* 6‡
Above grade when adjacent to public
walkway Note 1 Note 2
* Horizontal distance.
† 18 in. above roof surface in Canada.
‡ 36 in. to electric meter in Canada only.
NOTES:
1. When locating combustion-air and vent terminations, consideration must be
given to prevailing winds, location, and other conditions which may cause
recirculation of the appliance’s own flue products or the flue products of
adjacent vents. Recirculation can cause poor combustion, inlet condensate
problems, and accelerated corrosion of heat exchangers.
2. Vent termination can not terminate less than 2 ft horizontal and 7 ft above
public walkway or where condensate vapor or droplets may be a hazard.
Fig. 19—Combustion-Air and Vent Pipe Connections
A99024
AIR
FLOW
DOWNFLOW
COMBUSTION-
AIR
COMBUSTION-
AIR
VENT
VENT
Select 1 vent pipe connection and
1 combustion-air pipe connection.
NOTE:
—16—

Fig. 20—Short Vent (5 to 8 Ft) System A99025
DOWNFLOW TO SIDEWALLDOWNFLOW TO ROOF
COMBUSTION-AIR PIPE VENT PIPE
COMBUSTION-AIR PIPE
VENT PIPE
12″MIN
12″MIN
NOTE: A 12 In. minimum offset pipe section is recommended with
short (5 to 8 ft) vent systems. This recommendation is to reduce
excessive condensate droplets from exiting the vent pipe.
TABLE 7—MAXIMUM ALLOWABLE PIPE LENGTH (FT)
ALTITUDE UNIT SIZE TERMINATION
TYPE PIPE DIA (IN.)* NUMBER OF 90° ELBOWS
123456
0 to 2000 036080 048080
060080 2 Pipe or 2-In. Concentric
1-1/2 10 NA NA NA NA NA
2 555035303020
2-1/2 70 70 70 70 70 70
2001 to 3000 036080 048080
060080 2 Pipe or 2-In. Concentric 2 494430252515
2-1/2 70 70 70 70 70 70
3001 to 4000 036080 048080
060080 2 Pipe or 2-In. Concentric 2 464128232213
2-1/2 70 70 70 70 70 70
4001 to 5000‡ 036080 048080
060080 2 Pipe or 2-In. Concentric 2 443926212011
2-1/2 70 70 70 70 70 70
5001 to 6000‡ 036080 048080
060080 2 Pipe or 2-In. Concentric 2 4136231817 8
2-1/2 70 70 70 70 70 70
6001 to 7000‡ 036080 048080
060080 2 Pipe or 2-In. Concentric 2 3833211615 6
2-1/2 70 70 68 67 66 64
7001 to 8000‡ 036080 048080
060080 2 Pipe or 2-In. Concentric 2 3631191412NA
2-1/2 66 65 63 62 60 59
8001 to 9000‡ 036080 048080
060080 2 Pipe or 2-In. Concentric 2 3328171210NA
2-1/2 62 60 58 56 55 53
9001 to 10,000‡ 036080 048080
060080 2 Pipe or 2-In. Concentric 230251497NA
2-1/2 57 55 53 51 49 47
* Disk usage—Perforated disk assembly (factory-supplied in loose parts bag) MUST BE USED. See Combustion-Air and Vent Pipe Attachment section.
† Wide radius elbow.
‡ Vent sizing for Canadian installations over 4500 ft (1370 m) above sea level are subject to acceptance by the local authorities having jurisdiction.
NA—Not Allowed; pressure switch will not make.
NOTES:
1. Do not use pipe size greater than those specified in table or incomplete combustion, flame disturbance, or flame sense lockout may occur.
2. Size both the combustion-air and vent pipe independently, then use the larger diameter for both pipes.
3. Assume two 45° elbows equal one 90° elbow. Long radius elbows are desirable and may be required in some cases.
4. Elbows and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
5. The minimum pipe length is 5 ft for all applications.
—17—

2. When installing vent systems of short pipe length, use the
smallest allowable pipe diameter. Do not use pipe size
greater than required or incomplete combustion, flame
disturbance, or flame sense lockout may occur.
NOTE: Do not count elbows or pipe sections in terminations or
within furnace. See shaded areas in Fig. 22, 23, 24, 25, and 26.
EXAMPLE: An 036080 size furnace located in Indianapo-
lis, elevation 650 ft above sea level, could be installed in an
application requiring 3 elbows and 32 ft of vent pipe, along
with 5 elbows and 34 ft of combustion-air pipe. Table 7
indicates this application would allow a 2-in. diameter vent
pipe, but require a 2-1/2 in. diameter combustion air pipe
(2-in. pipe is good for 35 ft with 3 elbows, but only 30 ft
with 5 elbows). Therefore, 2-1/2 in. diameter pipe must be
used for both vent and combustion-air pipes since larger
required diameter must always be used for both pipes. If
same installation were in Albuquerque, elevation 5250 ft
above sea level, installation would require 2-1/2 in. vent
pipe and combustion-air pipe. At 5001- to 6000-ft eleva-
tion, 2-in. pipe is only good for 17 ft with 5 elbows, and
2-1/2 in. pipe is good for 70 ft with 5 elbows.
C. Combustion-Air and Vent Pipe Attachment
NOTE: All pipe joints must be watertight except attachment of
combustion-air pipe to inlet housing connection, since it may be
necessary to remove pipe for servicing.
1. Attach combustion-air pipe as follows:
a. Determine location of combustion-air intake pipe con-
nection to combustion-air intake housing as shown in
Fig. 19 for application.
b. Reposition combustion-air intake housing plug fitting in
appropriate unused intake housing connection.
(1.) The combustion-air intake plug fitting must be
installed in unused combustion-air intake housing.
This fitting must be attached by using RTV sealant,
or by drilling a 1/8-in. hole in fitting, using hole in
intake housing as a guide. Install a field-supplied
No. 6 or No. 8 sheet metal screw.
NOTE: DO NOT OVERTIGHTEN SCREW. Breakage to intake
housing or fitting may cause air leakage to occur.
(2.) A plugged drain connection has been provided on
this fitting for use when moisture is found in
combustion-air intake pipe and combustion box.
NOTE: Moisture in combustion-air intake may be result of
improper termination. Ensure combustion-air intake pipe is similar
to that shown in Fig. 22, 23, 24, 25, or 26 so it will not be
susceptible to areas where light snow or other sources of moisture
could be pulled in.
(3.) If use of this drain connection is desired, drill out
fitting’s tap plug with a 3/16-in. drill and connect a
field-supplied 3/8-in. tube. This tube should be
routed to open condensate drain for furnace and
A/C (if used), and should be trapped. (See Fig. 21.)
c. Insert perforated disk assembly (factory-supplied in
loose parts bag) in intake housing where combustion-air
intake pipe will be connected.
d. Install pipe support (factory-supplied in loose parts bag)
into selected furnace casing combustion-air pipe hole.
Pipe support should be positioned at bottom of casing
hole.
e. Insert 2-in. diameter pipe into intake housing.
NOTE: A 2-in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing.
(See Fig. 18.)
f. Drill a 1/8-in. hole in 2-in. combustion-air pipe using
hole in intake housing as a guide.
g. Install a field-supplied No. 6 or No. 8 sheet metal screw
into combustion-air pipe.
NOTE: DO NOT OVERTIGHTEN SCREW. Breakage to intake
housing or fitting may cause air leakage to occur.
NOTE: Do not attach combustion-air intake pipe permanently to
combustion-air intake housing since it may be necessary to remove
pipe for service of ignitor or flame sensor.
2. Attach vent pipe as follows:
a. Determine location of vent pipe connection to inducer
housing as shown in Fig. 19 for application.
b. Reposition elastomeric (rubber) inducer housing outlet
cap and clamp to appropriate unused inducer housing
connection. Tighten clamp.
WARNING: Inducer housing outlet cap must be in-
stalled and fully seated against inducer housing. Clamp
must be tightened to prevent any condensate leakage.
Failure to follow this warning could result in electrical
shock, fire, personal injury, or death.
c. Install pipe support (factory-supplied in loose parts bag)
into selected furnace casing vent pipe hole. Pipe support
should be positioned at bottom of casing hole.
d. Be certain that mating surfaces of inducer housing
connection elastomeric (rubber) coupling and 2-in. di-
ameter vent pipe are clean and dry. Assemble the
elastomeric vent coupling onto inducer housing connec-
tion. Insert 2-in. diameter vent pipe through elastomeric
coupling and fully onto inducer housing connection until
it bottoms on the internal stop and tighten both clamp(s)
to secure vent pipe to inducer housing (coupling may
have 1 or 2 clamps). Tighten clamp screw(s) to 30-in.-lb
of torque.
WARNING: Vent pipe must be installed and fully
seated against inducer housing internal stop. Clamp must
be tightened to prevent any condensate leakage. Failure to
follow this warning could result in electrical shock, fire,
personal injury, or death.
NOTE: A 2-in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing.
3. Working from furnace to outside, cut pipe to required
length(s).
Fig. 21—Intake Housing Plug Fitting Drain A99026
COMBUSTION –
AIR PIPE
BURNER
ENCLOSURE COMBUSTION – AIR
INTAKE HOUSING
3/8 ID
TUBE
TRAP
TO OPEN
DRAIN
3/16
DRILL
4″
MIN
—18—

4. Deburr inside and outside of pipe.
5. Chamfer outside edge of pipe for better distribution of
primer and cement.
6. Clean and dry all surfaces to be joined.
7. Check dry fit of pipe and mark insertion depth on pipe.
NOTE: It is recommended that all pipes be cut, prepared, and
preassembled before permanently cementing any joint.
8. After pipes have been cut and preassembled, apply gener-
ous layer of cement primer to pipe fitting socket and end of
pipe to insertion mark. Quickly apply approved cement to
end of pipe and fitting socket (over primer). Apply cement
in a light, uniform coat on inside of socket to prevent
buildup of excess cement. Apply second coat.
9. While cement is still wet, twist pipe into socket with 1/4
turn. Be sure pipe is fully inserted into fitting socket.
10. Wipe excess cement from joint. A continuous bead of
cement will be visible around perimeter of a properly made
joint.
11. Handle pipe joints carefully until cement sets.
12. Support combustion-air and vent piping a minimum of
every 5 ft (3 ft for SDR-21 or -26 PVC) using perforated
metal hanging strap.
13. Slope combustion-air and vent pipes toward furnace a
minimum of 1/4 in. per linear ft with no sags between
hangers.
14. Use appropriate methods to seal openings where vent and
combustion-air pipes pass through roof or side wall.
III. CONCENTRIC VENT AND COMBUSTION-AIR
TERMINATION KIT INSTALLATION
NOTE: If these instructions differ from those packaged with
termination kit, follow kit instructions.
Combustion-air and vent pipes must terminate outside structure. A
factory accessory termination kit must be installed in 1 of the
installations shown in Fig. 22, 23, 24, 25, or 26. Four termination
kits are available.
1. The 2-in. termination bracket kit is for 1-1/2 in., and 2-in.
diameter 2-pipe termination systems.
2. The 3-in. termination bracket kit is for 2-1/2 in. diameter
2-pipe termination systems.
3. The 2-in. concentric vent/air termination kit is for 1-1/2 in.,
2-in., and 2-1/2 in. diameter pipe systems when single
penetration of wall or roof is desired.
4. The 3-in. concentric vent/air termination kit is for 2-1/2 in.,
diameter pipe systems when single penetration of wall or
roof is desired.
NOTE: Shaded parts in Fig. 22, 23, 24, 25, and 26 are considered
to be termination. These components should NOT be counted
when determining pipe diameter. Roof termination is preferred
since it is less susceptible to damage, has reduced chances to take
in contaminants, and has less visible vent vapors. (See Fig. 22 or
23.) Sidewall termination may require sealing or shielding of
building surfaces with a corrosive resistance material due to
corrosive combustion products of vent system.
A. Extended Exposed Sidewall Pipes
Sidewall combustion-air and vent pipe terminations may be
extended beyond area shown in Fig. 25 or 26 in outside ambient by
insulating pipes as indicated in Table 8.
1. Determine combustion-air and vent pipe diameters, as
stated above, using total pipe length and number of elbows.
2. Using winter design temperature (used in load calculations),
find appropriate temperature for your application and fur-
nace model.
3. Determine required insulation thickness for exposed pipe
lengths.
NOTE: Pipe length (ft) specified for maximum pipe lengths
located in unconditioned spaces cannot exceed total allowable pipe
length as specified in Table 7.
B. Two-Pipe Termination Kit
1. Determine location for termination.
Consideration of the following should be made when
determining an appropriate location for termination kit.
a. Comply with all clearance requirements as stated in
Table 6.
b. Termination kit should be positioned where vent vapors
will not damage plants/shrubs or air conditioning equip-
ment.
c. Termination kit should be positioned so that it will not be
affected by wind eddy (such as inside building corners)
or allow recirculation of flue gases, airborne leaves, or
light snow.
d. Termination kit should be positioned where it will not be
damaged by or subjected to foreign objects, such as
stones, balls, etc.
e. Termination kit should be positioned where vent vapors
are not objectionable.
2. Cut 2 holes, 1 for each pipe, of appropriate size for pipe size
being used.
3. Loosely install elbow in bracket and place assembly on
combustion-air pipe.
Roof terminations—Loosely install pipe coupling on prop-
erly cut vent pipe. Coupling must be positioned so bracket
will mount as shown in Fig. 22.
For applications using combustion-air pipe option, indi-
cated by dashed lines in Fig. 22, install 90° street elbow into
90° elbow, making U-fitting. A 180° U-fitting may be used.
Sidewall terminations—Install bracket as shown in Fig. 25
or 26.
For applications using vent pipe option indicated by dashed
lines in Fig. 25, rotate vent elbow 90° from position shown
in Fig. 25.
4. Disassemble loose pipe fittings. Clean and cement using
same procedures as used for system piping.
5. Check required dimensions as shown in Fig. 22, 25, or 26.
C. Concentric Vent/Air Termination Kit
1. Determine location for termination.
Consideration of the following should be made when
determining an appropriate location for termination kit.
a. Comply with all clearance requirements as stated in
Table 6.
b. Termination kit should be positioned where vent vapors
will not damage plants/shrubs or air conditioning equip-
ment.
c. Termination kit should be positioned so it will not be
affected by wind eddy (such as inside building corners)
or that may allow recirculation of flue gases, airborne
leaves, or light snow.
d. Termination kit should be positioned where it will not be
damaged by or subjected to foreign objects, such as
stones, balls, etc.
e. Termination kit should be positioned where vent vapors
are not objectionable.
—19—

Fig. 25—Sidewall Termination of 12 in. or MoreA87225
MAINTAIN 12 IN.
CLEARANCE
ABOVE HIGHEST
ANTICIPATED SNOW
LEVEL OR GRADE,
WHICHEVER IS
GREATER.
90°
VENT
12 IN. SEPARATION
BETWEEN BOTTOM OF
COMBUSTION AIR AND
BOTTOM OF VENT
BRACKET
COMBUSTION-AIR
12″ MINIMUM
OVERHANG OR ROOF
Fig. 23—Concentric Vent and Combustion-Air Roof
Termination (Preferred)
A93054
COMBUSTION
AIR
MAINTAIN 12 IN.
(18 IN. FOR CANADA)
MINIMUM CLEARANCE
ABOVE HIGHEST
ANTICIPATED SNOW
LEVEL. MAXIMUM OF
24 IN. ABOVE ROOF.
VENT
Fig. 22—Roof Termination (Preferred) A87224
18″ MAXIMUM
COMBUSTION
AIR
COUPLING
ROOF
VENT
BRACKET
VERTICAL SEPARATION
BETWEEN COMBUSTION
AIR AND VENT
8 3/4″ FOR 3″ KIT
6 3/4″ FOR 2″ KIT
MAINTAIN 12 IN. MINIMUM
CLEARANCE ABOVE HIGHEST
ANTICIPATED SNOW LEVEL.
MAXIMUM OF 24 IN. ABOVE ROOF.
Fig. 26—Sidewall Termination of Less than 12 in.
A87226
MAINTAIN 12 IN.
CLEARANCE
ABOVE HIGHEST
ANTICIPATED SNOW
LEVEL OR GRADE,
WHICHEVER IS
GREATER.
90°
VENT
12 IN. SEPARATION
BETWEEN BOTTOM OF
COMBUSTION AIR AND
BOTTOM OF VENT
BRACKET
COUPLING
12″ MINIMUM
OVERHANG OR ROOF
COMBUSTION-AIR
(ELBOW PARALLEL
TO WALL)
Fig. 24—Concentric Vent and Combustion-Air Side
Termination
A93055
MAINTAIN 12 IN.
CLEARANCE
ABOVE HIGHEST
ANTICIPATED SNOW
LEVEL OR GRADE,
WHICHEVER IS
GREATER.
COMBUSTION-AIR
VENT
1″ MAXIMUM
12″ MINIMUM
OVERHANG OR ROOF
—20—