Bryant 349HAV Series, 349HAV036050, 349HAV036075, 349HAV048075, 349HAV048100 Installation, Start-up, And Operating Instructions Manual

installation, start-up,
and operating instructions

HORIZONTAL INDUCED-COMBUSTION
GAS FURNACE
SIZES 050—125, SERIES B

NOTE: Read the entire instruction manual before starting the
installation.

This symbol → indicates a change since the last issue.

INDEX

Page

SAFETY CONSIDERATIONS ................................................1-2

Clearances From Combustible Materials.................................1

INTRODUCTION.......................................................................2-3

Dimensional Drawing...............................................................2

LOCATION....................................................................................3

General......................................................................................3

Furnace Location Relative to Cooling Equipment..................3

Hazardous Locations.................................................................3

AIR FOR COMBUSTION AND VENTILATION...................3-5

General...................................................................................3-4

Unconfined Space.....................................................................4

Confined Space......................................................................4-5

Contaminated Combustion Air.................................................5

INSTALLATION........................................................................5-9

Duct Work Recommendations..................................................5

Horizontal Attic Installation.....................................................6

Horizontal Crawlspace Installation ..........................................6

Filter Arrangement....................................................................6

Gas Piping..............................................................................6-7

Reversing Procedure..............................................................7-9

ELECTRICAL CONNECTIONS.............................................9-11

115-v Wiring........................................................................9-11

Wiring Diagram......................................................................10

24-v Wiring.............................................................................11

Accessories..............................................................................11

VENTING...............................................................................11-13

General Venting Requirements.........................................11-12

Pre-Installation Vent System Inspection................................12

Removal of Existing Furnace from Common

Venting System..................................................................12

Metal Vent Installations..........................................................12

Masonry Chimney Installations..............................................12

Multistory Installations...........................................................12

Sidewall Venting Installations................................................12

SEQUENCE OF OPERATION...................................................13

Heating Mode..........................................................................13

Cooling Mode .........................................................................13

START-UP, ADJUSTMENT, AND SAFETY CHECK.......13-18

General....................................................................................13

Remove Shipping Bracket......................................................13

Purge Gas Lines......................................................................13

Operational Checkout .............................................................13

Adjustments .......................................................................14-17

Adjust Pilot Flame..................................................................14

Set Gas Input Rate ............................................................14-17

Set Temperature Rise..............................................................17

Set Blower Off Delay.............................................................17

Set Thermostat Heat Anticipator............................................17

Check Safety Controls.......................................................17-18

CHECKLIST................................................................................18

349HAV

Cancels: II 349H-50-4 II 349H-50-5

®

SAFETY CONSIDERATIONS

Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified person­nel should install, repair, or service heating equipment.

Untrained personnel can perform basic maintenance functions
such as cleaning and replacing air filters. All other operations must
be performed by trained service personnel. When working on
heating equipment, observe precautions in the literature, on tags,
and on labels attached to or shipped with the unit and other safety
precautions that may apply.

TABLE 1—ATTIC, CLOSET*, OR ALCOVE CLEARANCES

FROM COMBUSTIBLE MATERIALS (IN.)

UNIT SIZE 050, 075, 100, & 125

Sides 6
Back 6
Top of Plenum 2
Vent Connector 6
Front Casing 6†
Front Service 30

* For closet installations, refer to Air for Combustion and Ventilation section.
† Measured from end of inducer motor.

WARNING: Failure to comply with all of the above
clearances will create a fire hazard.

→

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 the furnace and in instructions or
manuals, be alert to the potential for personal injury.

Understand the signal words DANGER, WARNING, and CAU­TION. These words are used with the safety-alert symbol. DAN­GER identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies a hazard 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.

ama

CANADIAN GAS ASSOCIATION

APPROVED

R

6-98

.

—1—

These instructions cover minimum requirements 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 up with changing residen­tial construction practices. We require these instructions as a
minimum for a safe installation.

INTRODUCTION

The design of the 349HAV Horizontal Induced-Combustion Gas
Furnace is A.G.A./C.G.A. certified as a Category I furnace for
natural and propane gases and for installation in alcoves, base­ments, crawlspaces, utility rooms, and attics. The design of the
horizontal gas-fired furnace is A.G.A./C.G.A. certified for instal­lation on noncombustible floors. This furnace may be installed on
combustible wood flooring, however, it may not be installed
directly on carpeting, tile, or other combustible material other than
wood. The design of this furnace line is not A.G.A. certified for
installation in recreational vehicles, manufactured housing (mobile
homes), or outdoors.
The furnace is shipped as a packaged unit, complete with burners
and controls, and requires a 115-v line voltage connection to
junction box, a thermostat hook-up as shown in the wiring
diagram, and a gas line connection. The furnace is shipped in the
horizontal left configuration (for right-to-left airflow) but is easily
converted to the horizontal right configuration (for left-to-right
airflow). Refer to Reversing Procedure section for details.
The furnace is designed to interface with split system cooling
equipment (approved by UL) to provide year-round air condition­ing. The blower is sized for both heating and cooling, and the
furnace control includes a cooling fan relay.

Before installing the furnace, refer to the current edition of the
NFGC and the NFPA 90B. Canadian installations must be installed
in accordance NSCNGPIC and all authorities having jurisdiction.
For a copy of the NFGC NFPA54/Z223.1, contact International
Approval Services U.S. Inc., 8501 E. Pleasant Valley Road,
Cleveland, OH 44131 or National Fire Protection Association Inc.,
Batterymarch Park, Quincy, MA 02269. For a copy of NFPA 90B,
contact National Fire Protection Association Inc., Batterymarch
Park, Quincy, MA 02269.

Before installing 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. Canadian installations must be made in accordance with
CAN/CGA-B149 Installation Codes and authorities having juris­diction.

→

Installations must comply with the regulations of the serving gas
supplier and the local building, heating, plumbing, or other codes
in effect in the area in which the installation is made. In the
absence of local codes, the installation must conform with the
NFGC, NFPA No. 54-1996/ANSI Z223.1-1996.

CAUTION: Application of this furnace should be in­doors with special attention given to vent sizing and
material, gas input rate, air temperature rise, and unit
sizing. Improper installation or misapplication of the
furnace can require excessive servicing or cause prema­ture component failure.

(EXTEND BLOWER DOOR)

5

⁄8″

D ( NUMBER OF CELLS)

3 1⁄2″

1 3⁄4″

T-STAT

CONNECTION

1

⁄2-IN. GAS CONNECTION

A

19 1⁄2″

5

⁄16″

B

7

5 5⁄8″

(HIGH AIR FLOW UNITS ONLY)

2 1⁄2″

10″

⁄8″

26 5⁄8″

19 1⁄4″

7″

(2 PLACES)

7

⁄8-IN. ELECTRICAL

CONNECTION

28 7⁄8″

50″

C

4-IN. DIA VENT
CONNECTION

18″

5

4 9⁄16″

6 5⁄16″

4 1⁄8″

⁄8″

1 7⁄8″

5

⁄16″

B

21 3⁄8″

23 1⁄8″

7

⁄8″

A

AIR FLOW

5 7⁄8″

DIMENSIONS (IN.)

UNIT DIMENSIONS

UNIT SIZE

Length

036050 50 13-1/2 23-1/8 11-5/8 21-3/8 Flush 2 112
036075 50 13-1/2 23-1/8 11-5/8 21-3/8 Flush 3 121
048075 50 13-1/2 23-1/8 11-5/8 21-3/8 1 3 125
048100 50 17 23-1/8 15-1/8 21-3/8 Flush 4 141
060100 50 17 23-1/8 15-1/8 21-3/8 1 4 149
060125 50 20-1/2 23-1/8 18-5/8 21-3/8 Flush 5 161

* High airflow units only.

Width

A

Height

DUCT SUPPLY

AND RETURN

OPENINGS

Width

B

Height C D

EXTENDED

BLOWER

DOOR*

NUMBER
OF HEAT

EXCHANGERS

Fig. 1—Dimensional Drawing

A96068

NET

WEIGHT

(LB)

—2—

This furnace is designed for a minimum continuous return-air
temperature of 60°F db or intermittent operation down to 55°F db
such as when used with a night setback thermostat. Return-air
temperature must not exceed a maximum of 85°F db.

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, your distributor, or your

branch for information or assistance. The qualified in-

staller 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.

Locate furnace where available electrical and gas supplies meet the
specifications on furnace rating plate.

Line contact is only permissible between lines formed by the
intersection of furnace top and front and back sides and building
joists, studs, or framing. (See Fig. 2.)

ROOF

LINE CONTACT ONLY
PERMISSIBLE BETWEEN
TOP CORNERS OF
FURNACE AND BUILDING
JOISTS, STUDS, OR
FRAMING.

For accessory installation details, refer to the applicable installa­tion literature.
NOTE: Remove all shipping brackets and materials before oper­ating furnace.

LOCATION

I. GENERAL

CAUTION: Do not install furnace in a corrosive or

contaminated atmosphere. Make sure all combustion and

circulating air requirements are followed, in addition to

all local codes and ordinances.

Do not use this furnace during construction when adhe-

sives, sealers, and/or new carpets are being installed. If

the 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 cause corrosion of the heat exchangers

and metal vent system. Some of these compounds are

found in paneling and dry wall adhesives, paints, thin-

ners, masonry cleaning materials, and many other sol-

vents commonly used in the construction process. Exces-

sive exposure to contaminated combustion air will result

in safety and performance related problems.

This furnace may be located in an attic, basement, crawlspace,
alcove, or suspended from the ceiling of a utility room or
basement.

WARNING: Do not install the furnace on its back or

side. Safety control operation will be adversely affected.

Never connect return-air ducts to the back of the furnace.

Failure to follow this warning could result in a fire,

personal injury, or death.

KEEP ALL INSULATING MATERIAL
CLEAR OF FURNACE. INSULATING
MATERIAL MAY BE COMBUSTIBLE.

A96069

Fig. 2—Attic Installation Showing Point Contact

For attic installations, the passageway and servicing area adjacent
to furnace should be floored.

If furnace is to be installed in a crawlspace, consult local codes.
Use of a concrete pad 1 to 2 in. thick is recommended.

II. FURNACE LOCATION RELATIVE TO COOLING
EQUIPMENT

The cooling coil must be installed parallel with or on the
downstream side of the furnace to avoid condensation in the heat
exchanger. When installed parallel with a furnace, dampers or
other means used to control the flow of air must prevent chilled air
from entering the furnace. If the dampers are manually operated,
they must be equipped with a means to prevent operation of either
unit unless the damper is in the full-heat or full-cool position.

III. HAZARDOUS LOCATIONS

When furnace is installed in a residential garage, it must be
installed so that the burners and ignition source are located a
minimum of 18 in. above the floor. Furnace must be located or
protected to avoid physical damage by vehicles.

When furnace is installed in a public garage, airplane hangar, or
another building having a hazardous atmosphere, the unit must be
installed in accordance with the requirements of the National Fire
Protection Association, Inc.

WARNING: Do not place combustible material on fur­nace jacket. Failure to comply with this warning will
cause an explosion.

When a furnace is installed so that the supply ducts carry air to
areas outside the space containing the furnace, return air must also
be handled by duct(s) sealed to furnace casing and terminating
outside the space containing furnace to ensure there will not be a
negative pressure condition within the equipment room or space.
This furnace must be located so electrical components are pro­tected from water.
Locate furnace close to the chimney/vent and as near the center of
air distribution system as possible. The furnace should not be
connected to an operating chimney that also serves a solid fuel
burning appliance.
Provide ample space for servicing and cleaning. Always comply
with the minimum fire protection clearances shown on the unit
rating plate and in Table 1. A clurance of at least 30 in. should be
provided at front of unit for servicing.

WARNING: This furnace is not watertight and is not
designed for outdoor installation. This furnace shall be
installed in such a manner as to protect the electrical
components from water. Outdoor installation would lead
to a hazardous electrical condition and premature com­ponent failure.

AIR FOR COMBUSTION AND VENTILATION

I. GENERAL

Provisions for adequate combustion and ventilation air must be
provided in accordance with Section 5.3, Air for Combustion and
Ventilation, of the NFGC, or applicable provisions of local
building codes.

—3—

Canadian installations must be installed in accordance with the
NSCNGPIC and all authorities having jurisdiction.

WARNING: Do not block combustion air openings in
furnace. Any blockage will result in improper combustion
and may result in a fire hazard or unsafe condition.

CAUTION: Air for combustion must not be contami­nated by halogen compounds which include fluoride,
chloride, bromide, and iodide. These elements are found
in aerosol sprays, detergents, bleaches, cleaning solvents,
salts, air fresheners, and other household products.
Excessive exposure to contaminated combustion air will
result in safety and performance related problems.

CAUTION: The operation of exhaust fans, kitchen ven­tilation fans, clothes dryers, or fireplaces could create a
negative pressure condition at the furnace. Make-up air
must be provided for the ventilation devices, in addition
to that required by the furnace.

All fuel-burning equipment must be supplied with air for combus­tion of the fuel. Sufficient air MUST be provided to ensure there
will not be a negative pressure in the equipment room or space. In
addition, a positive seal MUST be made between furnace cabinet
and return-air duct to avoid pulling air from burner area and draft
safeguard opening.

The furnace shall be installed in a location in which the facilities
for ventilation permit satisfactory combustion of gas, proper
venting, and maintenance of ambient temperature at safe limits
under normal conditions of use. The furnace shall be located so as
not to interfere with proper circulation of air.

In addition to air needed for combustion, process air must be
provided as required for cooling of equipment or material, con­trolling dew point, heating, drying, oxidation or dilution, safety
exhaust, and odor control. Air must be supplied for ventilation,
including all air required for comfort and proper working condi­tions for personnel.

CAUTION: Whenever this furnace is installed in an area
along with 1 or more gas appliances, the total Btuh input
of all appliances must be included when determining the
free area requirements for combustion and ventilation
openings.

The requirements for combustion and ventilation air depend upon
whether the furnace is located in a confined or unconfined space.

II. UNCONFINED SPACE

An unconfined space must have at least 50 cu ft for each 1000
Btuh of input for all appliances such as furnaces, clothes dryer,
water heaters, etc. in that space. Rooms communicating with the
space in which the appliances are installed through openings not
furnished with doors are considered a part of the unconfined space.

If the unconfined space is of unusually tight construction, air for
combustion and ventilation MUST come from either the outdoors
or spaces freely communicating with the outdoors. Combustion
and ventilation openings must be sized the same as for a confined

space. A minimum opening with a total of at least 1 sq in. per 5000
Btuh of total input rating for all equipment must be provided.
Return air must not be taken from the room unless an equal or
greater amount of air is supplied to the room.

III. CONFINED SPACE

A confined space has less than 50 cu ft for each 1000 Btuh of the
total input ratings of all appliances installed in that space.

A confined space MUST have 2 permanent openings, 1 within 12
in. of the ceiling and the other within 12 in. of the floor.

NOTE: In determining the free area of an opening, the blocking
effect of the louvers, grilles, and screens must be considered. If the
free area of a louver or grille design is unknown, assume that wood
louvers have a 20 percent free area and metal louvers or grilles
have a 60 percent free area. Screens, when used, must not be
smaller than 1/4-in. mesh. Louvers and grilles must be constructed
so they cannot be closed.

The size of the openings depends upon whether the air comes from
inside or outside of the structure.

A. All Air from Inside the Structure:

1. Each opening MUST have at least 1 sq in. of free area per
1000 Btuh of the total input for all equipment within the
confined space, but not less than 100 sq in. per opening.

For Example:

349HAV FURNACE

INPUT BTUH

50,000 100

75,000 100
100,000 100
125,000 125

FREE AREA PER

OPENING (SQ IN.)

2. If the building is of unusually tight construction, in addition
to the 2 permanent openings that freely communicate with
an unconfined space, a permanent opening directly commu­nicating with the outdoors should be provided. This opening
should have a minimum free area of 1 sq in. per 5000 Btuh
of total input rating for all equipment in the enclosure.

3. If the furnace is installed on a raised platform to provide a
return-air plenum, and return air is taken directly from the
hallway or space adjacent to the furnace, all air for
combustion must come from outdoors.

B. All Air from Outdoors:

1. If combustion air is taken from outdoors through vertical
ducts, the openings and ducts MUST have at least 1 sq in.
of free area per 4000 Btuh of the total input for all
equipment within the confined space.

For Example:

349HAV FURNACE

INPUT BTUH

50,000 12.5 4

75,000 18.8 5
100,000 25.0 6
125,000 31.3 7

FREE AREA PER

OPENING (SQ IN.)

ROUND PIPE

(IN. DIA)

2. If combustion air is taken from the outdoors through
horizontal ducts, the openings and ducts MUST have at
least 1 sq in. of free area per 2000 Btuh of the total input for
all equipment within the confined space.

—4—

For Example:

349HAV FURNACE

INPUT BTUH

50,000 25.0 6

75,000 37.5 7
100,000 50.0 8
125,000 62.5 9

FREE AREA PER

OPENING (SQ IN.)

ROUND PIPE

(IN. DIA)

When ducts are used, they must be of the same cross-sectional area
as the free area of the openings to which they connect. The
minimum dimension of rectangular ducts must not be less than 3
in.

IV. CONTAMINATED COMBUSTION AIR

Contaminated combustion air must be avoided in order not to
adversely affect the long term life of furnace, especially heat
exchanger and burners.

The recommended source of combustion air is to use the outdoor
air supply. Use of indoor air in most applications is acceptable as
long as there is no exposure to the types of installation or
substances listed below and all provisions for indoor combustion
air meet the requirements for combustion air supply indicated in
the NFGC Section 5.3; CAN1-B149 Installation Codes; and/or any
applicable local codes.

A. Installations Requiring Outdoor Combustion Air

1. The following types of installations require OUTDOOR
AIR for combustion due to chemical exposures:

a. Commercial buildings
b. Buildings with indoor pools
c. Furnaces installed in laundry rooms
d. Furnaces installed in hobby or craft rooms
e. Furnaces installed near chemical storage areas

2. Exposure to the following substances in the combustion air
supply also require OUTDOOR AIR for combustion:

a. Permanent wave solutions
b. Chlorinated waxes or cleaners
c. Chlorine based swimming pool chemicals
d. Water softening chemicals
e. De-icing salts or chemicals
f. Carbon tetrachloride
g. Halogen-type refrigerants
h. Cleaning solvents (such as perchloroethylene)
i. Printing inks, paint removers, varnishes, etc.
j. Hydrochloric acid
k. Cements and glues
l. Anti-static fabric softeners for clothes dryers
m. Masonry acid washing materials

The following recommendations should be followed when install­ing duct work:

1. Install locking type dampers in all branches of individual
ducts to balance out system. Dampers should be adjusted to
impose proper static at outlet of furnace.

2. Noncombustible flexible duct connectors are recommended
to connect both supply- and return-air ducts to furnace.

3. In cases where return-air grille is located close to fan inlet,
there should be at least one 90° air turn between fan and
inlet grille. Further reduction in sound can be accomplished
by installing acoustical air turning vanes and/or lining
inside of duct with acoustical material.

4. It is recommended that outlet duct be provided with a
removable access panel. The opening shall be accessible
when furnace is installed and shall be of such a size that
heat exchanger can be viewed for possible openings using
light assistance or so a probe can be inserted for sampling
air stream. The access panel shall be designed so as to
prevent leaks when locked in position. If an air conditioning
coil is installed, access panel to coil can be used for this
purpose.

CAUTION: Air openings, intake and outlet pipes,
return-air grilles, and warm air registers must not be
obstructed.

WARNING: When supply ducts carry air circulated by
furnace to areas outside spaces containing furnace, return
air shall also be handled by a duct sealed to furnace
casing and terminating outside space containing furnace.
Incorrect duct work termination and sealing will create a
hazardous condition which could lead to bodily harm.

5. When installing furnace with cooling equipment for year­round operation, the following recommendations must be
followed for series or parallel airflow:

a. In series airflow applications, coil is mounted after

furnace in an enclosure in supply-air stream. The furnace
blower is used for both heating and cooling airflow.

WARNING: The coil MUST be installed on air dis­charge side of furnace. Under no circumstances should
airflow be such that cooled, conditioned air can pass over
furnace heat exchanger. This will cause condensation in
heat exchanger and possible failure of heat exchanger
which could lead to a fire hazard and/or a hazardous
condition which may lead to bodily harm. Heat exchanger
failure due to improper installation may not be covered by
warranty.

INSTALLATION
I. DUCT WORK RECOMMENDATIONS
IMPORTANT: This furnace is equipped with a metal heat

exchanger shipping bracket which must be removed before install­ing furnace. The No. 10 screws which fasten bracket to furnace
will interfere with attachment of outlet duct if not removed.
Remove bracket by removing No. 10 screws located on bottom
panel duct supply flange, rotating bracket forward and lifting out.

The proper sizing of warm air ducts is necessary to ensure
satisfactory furnace operation. Duct work should be in accordance
with the latest editions of U.S. NFPA-90A (Air Conditioning
Systems) and NFPA-90B (Warm Air Heating and Air Condition­ing Systems) or Canadian equivalent.

b. In parallel airflow installation, dampers must be pro-

vided to direct air over furnace heat exchanger when
heat is desired and over cooling coil when cooling is
desired.

IMPORTANT: The dampers should be adequate to prevent
cooled air from entering furnace. If manually operated, dampers
must be equipped with means to prevent operation of either
cooling unit or furnace unless damper is in full cool or full heat
position.

—5—

SHEET

30-IN. MIN
WORK AREA

METAL

Fig. 3—Typical Attic Installation

24″

24″

A96070

II. HORIZONTAL ATTIC INSTALLATION

The furnace can be installed horizontally for either left- or
right-side supply. See Fig. 3 for a typical attic installation and
Reversing Procedure section for reversing airflow direction.

CAUTION: In attic installations, it is necessary to keep
insulation at least 12 in. away from any furnace opening.
Some types of insulating materials are combustible.

1. Construct a working platform on location where all required
furnace clearances are met. (See Table 1 and Fig. 3.)

2. Position furnace in desired location.

3. Connect gas supply pipe. See Fig. 4 for typical gas piping.

4. Connect supply- and return-air ducts.

5. Install 24- X 24-in. sheet metal shield on platform in front
of controls as shown in Fig. 3.

III. HORIZONTAL CRAWLSPACE INSTALLATION

The furnace can be installed horizontally for either left- or
right-side supply. In a crawlspace, the furnace can either be hung
from floor joists or installed on suitable blocks or a pad. The
furnace can be suspended using steel pipe straps around each end
of furnace. These straps should be attached to furnace with sheet
metal screws and to floor joists with lag bolts. A framed assembly
of angle iron suspended with all-thread rod of suitable diameter
may be used to support the length of furnace. Refer to Fig. 1 for
size and weight of furnace. Care must be taken to allow for blower
door access.

The horizontal crawlspace installation is very similar to the attic.
Refer to Horizontal Attic Installation section, items 2, 3, 4, and 5.
A 24- X 24-in. sheet metal shield must be installed above the
controls for crawlspace installations. Extend sheet metal shield
over furnace top far enough to cover gas pipe entry hole.

IV. FILTER ARRANGEMENT

CAUTION: Never operate the unit without a filter or

with the filter removed. Failure to follow this caution can
result in a fire, personal injury, or death.

A factory-supplied filter and wire filter retainer are shipped with
furnace. After return-air duct has been connected to furnace, install
filter in blower compartment, just ahead of return-air plenum, and
secure it with wire filter retainer. The cross-mesh binding side of
filter should face blower. Refer to Table 2 for filter sizes.

TABLE 2—FILTER SIZE (IN.)

UNIT SIZE FILTER SIZE

036050 13X23
036075 13X23
048075 13X23
048100 16-1/2 X 23
060100 16-1/2 X 23
060125 20X23

V. GAS PIPING

Gas piping must be installed in accordance with national and local
codes. Refer to the current edition of the NFGC.

Canadian installations must be installed in accordance with the
NSCNGPIC and all authorities having jurisdiction.

Gas piping shall be of such size and so installed as to provide a
supply of gas sufficient to meet maximum demands without undue
loss of pressure between gas meter and furnace. It is recommended
that the gas supply line be a separate line running directly from
meter to furnace, unless existing gas line is of ample capacity.
Refer to Table 3 for recommended gas pipe sizing. Risers must be
used to connect to furnace and to meter.

Support all piping with appropriate straps, hangers, etc. Use a
minimum of 1 hanger every 72 in.

Joint compounds (pipe dope) should be applied sparingly and only
to male threads of joints. This pipe dope must be resistant to the
action of propane gas.

—6—

TABLE 3—MAXIMUM CAPACITY OF PIPE*

NOMINAL

IRON

PIPE
SIZE

(IN.)

1/2 0.622 175 120 97 82 73
3/4 0.824 360 250 200 170 151

1 1.049 680 465 375 320 285
1-1/4 1.380 1400 950 770 660 580
1-1/2 1.610 2100 1460 1180 1993 900

*Cu 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.

INTERNAL

DIAMETER (IN.)

LENGTH OF PIPE (FT)

10 20 30 40 50

NOTE: In order to make proper adjustments, minimum and
maximum gas supply pressure limits shown on rating plate must
not be exceeded.

Install a sediment trap in riser leading to furnace. The trap can be
installed by connecting a tee to riser leading to furnace, so that the
straight-through section of tee is vertical.

Then connect a capped nipple into lower end of tee. The capped
nipple should extend below the level of gas controls. Place a
ground joint union between gas control manifold and manual gas
shutoff valve. (See Fig. 4.)

Piping should be pressure tested in accordance with local and
national plumbing and gas codes before furnace has been attached.
If test pressure exceeds 0.5 psig (14-in. wc), the 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),
close manual shutoff valve located on gas valve before pressure
test. It is recommended that the ground joint union be loosened
before pressure testing.

CAUTION: Use a backup wrench when connecting the
gas pipe to the furnace to avoid damaging gas controls.

After all connections have been made, purge the lines and check
for leakage.

WARNING: Never purge a line into a combustion
chamber. Never use matches, candles, flame, or other
sources of ignition for the purpose of checking leakage.
Use a soap-and-water solution to check for leakage.
Failure to follow this warning could result in a fire,
explosion, personal injury, or death.

VI. REVERSING PROCEDURE

GAS

SUPPLY

MANUAL

SHUTOFF

VALVE

SEDIMENT

TRAP

THIS DRIP LEG MUST BE

INSTALLED WITH THE PIPE

CAP A MINIMUM OF 1 IN.

FROM FLOOR TO PERMIT

REMOVAL

UNION

A96071

Fig. 4—Typical Gas Piping

CAUTION: If a flexible connector is required or al-

lowed by the authority having jurisdiction, black iron
pipe shall be installed at the gas valve and extend a
minimum of 2 in. outside the furnace casing.

An accessible manual shutoff valve MUST be installed upstream
of furnace gas controls and within 72 in. 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. (The manifold
pressure tap on gas control meets this requirement.)

WARNING: Use the proper length of pipes to avoid
stress on the gas control manifold. A failure to follow this
warning could result in a gas leak resulting in a fire,
explosion, personal injury, or death.

Before any system of gas piping is finally put into service, it
should be carefully tested to determine if it is gas tight. The piping
must stand a pressure of 6 in. of mercury for a period of 10 minutes
or as required by local authority.

WARNING: Before proceeding with field reversal, en­sure that all electrical power is turned off and that all gas
piping is shut off and disconnected from the furnace.
Failure to do so could result in an extremely hazardous
condition and bodily harm.

This furnace may be field reversed allowing for a horizontal right
configuration (left-to-right airflow) instead of the factory posi­tioned horizontal left configuration (right-to-left airflow). (See Fig.

5.) Field reversal is accomplished in a convenient 3-step process.

1. Invert furnace so top panel is down.

2. Adjust manifold and burner opening plate.

3. Wire alternate limit switch.

A. Invert The Furnace

1. Carefully flip furnace on its top panel. Care should be taken
not to drop unit or let it rest on 1 of its ends.

2. Controls should now appear as in right-hand view of Fig. 5.

B. Adjust Manifold and Burner Opening Plate

1. Remove front and back burner removal covers located on
front and rear center panels.

2. Cut wire tie securing violet-colored rollout switch wires and
ignition wire to manifold assembly.

3. Disconnect all wires from gas valve.

CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper and
dangerous operation.

4. Remove both manifold retention places from burner box
and remove burner/manifold assembly. While removing
burner/manifold assembly, disconnect violet-colored rollout
switch wires from rollout switch. (See Fig. 6.)

5. On burner/manifold assembly, remove 2 screws that fasten
rollout switch bracket to rollout switch base bracket. (See
Fig. 7.)

—7—

ALTERNATE
LIMIT
SWITCH

BLOWER

DOOR

BLOWER

DOOR

ALTERNATE

LIMIT

SWITCH

CONTROL LAYOUT (AS SHIPPED)

Fig. 5—Control Layout for Reversal

Fig. 6—Removing Burner/Manifold Assembly

SWITCH BRACKET

CONTROL LAYOUT (FIELD REVERSED)

A91387

A96073

REMOVE

BASE BRACKET

A92306

Fig. 7—Rollout Switch Assembly

6. With rollout switch base bracket still attached to
burner/manifold assembly, turn assembly over so that pilot
burner is on top.

7. Place rollout switch bracket on rollout switch base so face
of switch is oriented toward heat exchanger.

8. Fasten bracket to base with screws removed in item 5. (See
Fig. 8.)

9. Remove burner opening inlet plate from inside burner box
and reinstall in burner box with word TOP (stamped on
part) in up position. (See Fig. 9.)

10. Replace manifold retention plate on side of furnace opposite
controls.

11. Before installing manifold, reconnect violet-colored rollout
switch wires to rollout switch.

12. Install burner/manifold assembly making sure manifold
bracket slides under manifold retention plate.

A96074

Fig. 8—Reattaching Rollout Switch Bracket

A96075

Fig. 9—Reversing Burner Opening Inlet Plate

13. Install manifold retention plate nearest gas valve. The
burner/manifold assembly should now be firmly attached to
furnace.

14. Reconnect wires to gas valve. Refer to furnace wiring
diagram.

—8—

15. Secure gas valve wires to manifold assembly with wire tie.

16. Replace burner removal covers on respective sides of
furnace.

17. Remove front blower door and reinstall so instructional
labels are rightside up.

NOTE: On high airflow models (75,000 and 100,000 Btuh), the
front and rear blower doors must be interchanged so that the
instructional labels are rightside up on both sides of furnace. Move
blower door knob to new front blower door.

C. Wire Alternate Limit Switch

1. Disconnect wires from limit switch located on front center
panel and reconnect wires to alternate limit switch on right
front panel. (See right-hand view of Fig. 5.)

2. Replace control box cover.

CAUTION: Do not connect aluminum wire between the
disconnect switch and the furnace. Use only copper wire.

Make all electrical connections in accordance with the National
Electric Code ANSI/NFPA 70-1996 and any local codes or
ordinances that might apply.

For Canadian installations, all electrical connections must be made
in accordance with CSA C22.1 Canadian Electrical Code, or
authorities having jurisdiction.

When replacing any original wiring, use only 105°C, AWG No. 16
copper wire.

→

Use a separate, fused branch electrical circuit containing a properly
sized fuse or circuit breaker for this furnace. See Table 4 for wire
size and specifications. A disconnecting means must be located
within sight of and readily accessible to the furnace.

WARNING: Limit switch wires MUST be moved to the
alternate limit switch when reversing the furnace to
ensure safe operation. Failure to follow this warning may
result in a hazardous operating condition.

ELECTRICAL CONNECTIONS

See Fig. 10 for a wiring diagram showing the proper field 115- and
24-v wiring connections. Check all electrical connections (both
factory and field) for tightness. In all instances, wiring to be done
and any replacement wire shall conform with the temperature
limitation for Type T wire (63°F/35°C rise).

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 to Table 4 for equipment electrical specifications.

NOTE 4

115-V

SINGLE

PHASE

GND

115-V

FIELD-SUPPLIED

DISCONNECT

FIVE

WIRE

THREE-WIRE

HEATING

ONLY

GND

24-V

TERMINAL

BLOCK

WRCGY

W

R

G

C
Y

WARNING: The cabinet must have an uninterrupted or
unbroken ground according to National Electrical Code,
ANSI/NFPA 70-1996, Canadian Electrical Code, CSA
C22.1, or local codes to minimize personal injury if an
electrical fault should occur. This ground 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 an electrical
shock, fire, or death.

NOTE: Proper polarity must be maintained for 115-v wiring for
ignition control to function properly. Connect "hot" wire H and
"ground" wire G as shown in Fig. 11.

CAUTION: If manual disconnect switch is to be
mounted on the furnace, select a location where a drill or
fastener will not contact electrical or gas components.

FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-, 208/230-, 460-V WIRING

THERMOSTAT
TERMINALS

GND

CONDENSING

UNIT

TWO
WIRE

FIELD-SUPPLIED
DISCONNECT

208/230- OR
460-V
THREE
PHASE

GNDGND

208/230-V
SINGLE
PHASE

GND

NOTE :

→ Fig. 10—Heating and Cooling Application Wiring Diagram

1. Connect Y-terminal as shown for proper cooling operation.

2. If any of the original wire, as supplied, must be replaced,
use same type or equivalent wire.

3. Proper polarity must be maintained for 115-v wiring.

4. Some thermostats require a "C" terminal connection as shown.

A98302

—9—

PRINTED CIRCUIT

LINE V

BOARD WIRINGBKBL

24V
LINE V

FACTORY WIRING

24V
LINE V

FIELD WIRING

24V

ORANGE WIRE NUT
GROUND

UNUSED MOTOR

LEAD

UNUSED MOTOR

LEAD

LEGEND

CONTINUOUS LOW SPEED FAN OPTIONS

CONSTANT

HEAT

COOL

CONSTANT

HEAT
COOL

CONTINUOUS LOW SPEED FAN WITH

OPTIONAL INTERUPT FAN SWITCH

CONSTANT

HEAT

COOL

CONSTANT

HEAT
COOL

BR
GR
OR
RD
RD/BK
VI
WH
YL

FAN
SWITCH

FAN
SWITCH

BLACK
BLUE
BROWN
GREEN
ORANGE
RED
RED/BLACK STRIPE
VIOLET
WHITE
YELLOW

JUMPER

LOW
MED

HIGH

LOW
MED
HIGH

LOW
MED
HIGH

LOW
MED
HIGH

LOW SPEED

HEAT CONNECTION

MEDIUM SPEED

HEAT CONNECTION

LOW SPEED

HEAT CONNECTION

MEDIUM SPEED

HEAT CONNECTION

L

LIMIT

P

PRESSURE SWITCH

ROS

ROLL OUT SWITCH*

BI

BLOWER INTERLOCK

CU

CONDENSING UNIT
MANUAL RESET

*

T

TRANSFORMER

F1

LOW VOLT. FUSE

N2

N2

N2

N2

TSTAT24V

GNDFT

NOTES:

1. Make field power supply connections to black and white wires
capped with orange wire nuts.

2. WARNING---unit must be grounded. Wiring must conform to NEC and
local codes.

3. If any of the original wire, as supplied with the furnace, must be replaced,
it must be replaced with wiring material having a temperature
rating of at least 105°C and be a minimum of 16 gage AWG copper strand wire.

4. Connect required motor lead to heat terminal on circuit board to deliver a
temperature rise within the range specified on the rating label. Connect
unused leads to the unused motor leads.

5. Set the heat anticipator on the thermostat at .40 amps.

6. Low voltage fuse 5 amp automotive type littlefuse 257005 or buss ATCS.

7. Both EAC and HUM terminals are 115v.

ROS

N.O.

PRESSURE SW.

CN23-3

COM

PS1
PS2 W1

N.C.

CN23-5

SV9501 HOT SURFACE PILOT

IGNITION SYSTEM CONTROL

CN23-2

CONTROL

LIMIT

CN23-1

X

24VAC

TRANSFORMER

CONDENSING

C

S2

K3

(115VAC)

N4

D1

N3

CN23-6

ST9120C2010 ELECTRONIC

FAN TIMER

W

G

C

R

Y

UNIT

TSTAT

GND

K2

COOL

INDUCER

MOTOR

S1

BI

GND

K1K2

100, 125

HEAT

50, 75

MED

CIRCULATION

LOW

HI

FAN

N2

N1

L1(H)

(DISCONNECT ON HOT LEG)

L2(N)115 VAC 1Ø 60 HZ POWER SUPPLY

POWER SUPPLY
115 VAC 1 PH 60 HZ
(DISCONNECT ON
HOT LEG)

L2 (N)

L1 (H)

50, 75K INPUT

100, 125K INPUT

71

72

W

N

T

I

1
2

Honeywell

SEE NOTE 7

CU

C

GYW

R

ST9120C-16

RD

WYGR

HORIZONTAL GAS FURNACE WITH HONEYWELL ST9120C FAN TIMER & SV9501 SMART VALVE

FACTORY SET

HEATING SPEED

50 & 75K INPUTS-LOW (L)

100 & 125K INPUTS-MEDIUM (M)

GND

WH

BI

12

S

D1

HUM EAC N N

UNUSED

MOTOR

LEADS

N

1

NEUTRAL

CIR BLWR

CONT

COOL

HEAT

F1

4C32

GND

1

XFMR

X

SEC

SEE NOTE 6

RD

BR

→ Fig. 11—Wiring Diagram

321

6

54

ENLARGED TOP VIEW 6-PIN PLUG (CN23)

INDOOR
BLOWER
& MOTOR

BK

BL

RD/BK WH

YL

OR

BR

BR

CAP.

C

L

H

M

43

21

WH

SV9501

BL

L

YL

VI

—10—

BK

PILOT

12 12 12 12

60 SEC

90 SEC 120 SEC 150 SEC

DELAY OFF DIP SWITCH SETTINGS

INDUCER
BLOWER

BK

BL

24V COM

24V PRESS. SW

24V HOT

OUTPUT

EFT

VI

P

ROS

*

VI

A98303

→ TABLE 4—ELECTRICAL DATA

UNIT SIZE

HERTZ—

PHASE

036050 115—60—1 127 104 9.3 14 30 15
036075 115—60—1 127 104 9.9 14 28 15
048075 115—60—1 127 104 11.3 14 25 15
048100 115—60—1 127 104 9.9 14 28 15
060100 115—60—1 127 104 13.1 12 34 20
060125 115—60—1 127 104 11.3 14 25 15

* Permissible limits of the voltage range at which the unit will operate satisfactorily.
† 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.

VOLTS—

OPERATING

VOLTAGE RANGE

Max* Min*

MAX
UNIT

AMPS

MIN

WIRE

SIZE

MAX WIRE

LENGTH†

(FT)

MAX FUSE

OR CIRCUIT

BREAKER‡ AMPS

II. 24-V WIRING

Make field 24-v thermostat connections at the 24-v terminal block.
Connect Y terminal as shown in Fig. 10 for proper cooling
operation. The 24-v control board is marked for easy connection of
field wiring. (See Fig. 12.)

3

1

S

T

W

I

N

DI 1

S

2 HUM EAC

SPEED

MOTOR

UNUSED

UP

N

LEADS

NEUTRAL

CIR

NN

CY

234 C

BLWR

COOL

HEAT

CONT

CG

YW R

XX

SEC

XFMR

5

A96103

Fig. 12—Control Board

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

Install accessories per manufacturer’s instructions. Other than
wiring for thermostat, a minimum of type T wire (63°F/35°C rise)
must be used.

1. Electronic Air Cleaner (EAC)
Two 1/4-in. quick-connect terminals marked EAC and N

are provided for EAC connection. (See Fig. 12.) These
terminals are energized with 115v (0.5-amp maximum)
during blower motor operation.

2. Humidifier (HUM)
Two 1/4-in. quick-connect terminals marked HUM and N

are provided for 115-v humidifier connection. (See Fig. 12.)
These terminals are energized with 115v (0.5-amp maxi­mum) during any call for heat.

Cycle test furnace and accessories twice to ensure proper opera­tion.

VENTING

I. GENERAL VENTING REQUIREMENTS

→

Venting for furnace should be to the outside and in accordance
with local codes or requirements of local utility. In the absence of
local codes, venting should conform to the NFGC Part 7 or
CAN/CGA-B149 Installation Codes Section 7, the vent manufac­turer’s Installation Instructions, and the A.G.A./GAMA Venting
Tables supplied with furnace.

These furnaces are equipped with induced-combustion blowers
and are classified as Category I forced air furnaces in accordance
with ANSI/A.G.A. Z21.47 and C.G.A. 2.3 Central Furnace Stan­dards. Category I furnaces use non-positive, non-condensing vent
systems, and may be connected to lined masonry chimneys which
have been sized and installed per the enclosed procedures. Cat­egory I furnaces can not be vented into a vent system with any
Category II, III, or IV appliance. It must be vented vertically or
nearly vertically, unless installed with a listed mechanical venter in
accordance with horizontal venting instructions in the Horizontal
Venting section below. A Category I furnace must not be con­nected to any portion of a mechanical draft system operating under
positive pressure.

Venting of these furnaces into a lined masonry chimney could
form flue gas condensate due to cold surfaces and oversizing. If
condensate is present in the masonry chimney, a drain must be
provided to prevent condensate flow into the vent connector and
furnace. (Refer to the NFGC, Section 7.9 for additional informa­tion on condensate drains.) Field experience on induced­combustion furnaces has shown that venting through a properly
sized Type B-1 vent significantly reduces vent condensation.
Condensate is acidic and could corrode vent materials. Therefore,
the manufacturer suggests (but does not require) that these
furnaces be connected to vent systems constructed of Type B-1
vent material.

This furnace may be common vented only with other Category I
appliances. Common venting is allowed as permitted by national
and/or local codes. Refer to the NFGC Venting Tables supplied
with furnace for proper sizing and setup.

The vent must be terminated with a listed vent cap or roof
assembly. This venting must be installed in accordance with the
vent manufacturer’s Installation Instructions and be in accordance
with all local and/or national codes.

The following requirements are provided for a safe venting
system:

1. Be sure chimney flue is clear of any dirt or debris.

2. Be sure chimney is not servicing an open fireplace.

3. Never reduce pipe size below outlet size of furnace without
checking the NFGC Venting Tables supplied with furnace.

4. All pipe should be supported using proper clamps and/or
straps. These supports should be at least every 4 ft.

5. All horizontal runs of pipe should slope upward at least 1/4
in. per ft from furnace to vent terminal.

—11—

6. All runs of pipe should be as short as possible with as few
turns as possible.

7. Seams should be tightly joined and checked for leaks.

8. The flue pipe must not extend into chimney but be flush
with inside wall.

9. The chimney or vent pipe must extend at least 3 ft above the
highest point where it passes through a roof of a building
and at least 2 ft higher than any portion of a building within
a horizontal distance of 10 ft. It shall also extend at least 5
ft. above highest connected equipment flue collar.

NOTE: The NFGC venting tables MUST be used; DO NOT use
BDP’s Single-Stage Vent Tables for Category I Fan-Assisted
Furnaces, as they are based on different input ratings.

II. PRE-INSTALLATION VENT SYSTEM INSPECTION

Before furnace is installed, it is highly recommended that any
existing vent system be completely inspected.

For a chimney or Type B vent, this should include the following:

1. Inspection for any deterioration in chimney or Type B vent.
If deterioration is discovered, the chimney must be repaired
or Type B vent must be replaced.

2. Inspection to ascertain that vent system is clear and free of
obstructions. Any blockage must be cleared before install­ing furnace.

3. Cleaning chimney or Type B vent if previously used for
venting a solid fuel burning appliance or fireplace.

4. Confirming that all unused chimney or Type B vent
connections are properly sealed.

5. Verification that chimney is properly lined and sized per
applicable codes.

III. 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 opera­tion, while any other appliances connected to the venting system
are not in operation:

1. Seal any unused openings in the venting system.

2. Inspect the venting system for proper size and horizontal
pitch as required in the NFGC or the CAN/CGA B149
Installation Codes and these instructions. Determine that
there is no blockage or restriction, 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 opera­tion. 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 damp­ers, 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 NSC­NGPIC.

IV. METAL VENT INSTALLATIONS

The furnace is approved for use with Type B vent that terminates
through the roof. Refer to the NFGC Venting Tables supplied with
furnace for proper sizing and setup of this furnace with Type B
vent for a dedicated vent system or a common vented system.

V. MASONRY CHIMNEY INSTALLATIONS

This furnace can be common vented into an existing tile lined
masonry chimney provided:

1. The chimney is currently serving at least 1 drafthood
equipped appliance.

2. The vent connectors and chimney are sized in accordance
with the NFGC Venting Tables supplied with furnace.

This furnace must not be vented ALONE into an existing masonry
chimney (either tile lined or unlined) unless the chimney is also
lined with either a Type B vent system or a listed single-wall metal
lining system (as specified in the NFGC Venting Tables). Both of
these systems must be sized in accordance with the NFGC Venting
Tables supplied with furnace.

Before venting this furnace into a chimney, check chimney for
deterioration and repair if necessary.

This furnace must not be vented into a chimney serving a separate
appliance designed to burn solid fuel.

Type B vent connector must be used on all installations. It must be
sized per the NFGC Venting Tables supplied with furnace.

VI. MULTISTORY INSTALLATIONS

For multistory installations, refer to Appendix G of the NFGC or
Canadian Standard CAN/CGA-B149. Additional vent connectors
should be sized per the enclosed instructions.

VII. SIDEWALL VENTING INSTALLATIONS
A. General

This furnace is A.G.A. and C.G.A. designed certified for sidewall
venting through an outside wall by use of the following auxiliary
draft inducer:

Field Controls Company Model No. DGF-2 sidewall vent­ing kit.

Follow Installation Instructions supplied with DGF-2 kit.
The minimum vent length is 5 ft and the maximum is 60 ft.

B. Location Requirements for Sidewall Venting

Locate vent terminal adhering to the following minimum clear­ances:

1. Vent terminal must be located at least 1 ft above the grade
or at least 1 ft above normal expected snowfall.

2. Avoid installing vent terminal above public walkways. If
this is not possible, install terminal at least 7 ft above
walkway.

3. Vent terminal should be at least 4 ft to the side of and at
least 1 ft above doors and windows.

4. Vent terminal should be at least 3 ft above any forced air
inlet located within 10 ft.

5. Vent terminal should be located at least 6 ft from the
combustion-air intake of another appliance.

6. Vent terminal should be located at least 4 ft above any
electric or gas meters, regulators, and relief equipment.

—12—

SEQUENCE OF OPERATION

Using the schematic diagram in Fig. 11, follow the sequence of
operation through the different modes. This furnace has a unique
control system. Read and follow the wiring diagram very carefully.

I. HEATING MODE

When wall thermostat calls for heat, the R-W circuit closes.

1. Inducer start-up sequence—Power from transformer ener­gizes fan control board. The fan control energizes the
induced-draft blower motor. Pressure switch P normally
open contacts close to energize ignition module.

2. Ignition module self-check—Upon being energized, the
ignition module performs a 2-sec self-check. The ignition
module checks for the presence of flame. If flame is present
when it should not be, the module energizes the blower. The
gas pilot valve remains closed, and ignitor is not energized.
If no flame is detected, the module initiates the ignition
sequence.

3. Ignition sequence—The ignition module energizes the hot
surface pilot ignitor. The module then checks for a missing
or broken ignitor. If ignitor is faulty, there is no further
system response. If ignitor is functional, the pilot gas valve
is energized and gas is allowed to flow to pilot where it is
ignited. A flame sensing period then begins.

4. Flame sensing—Pilot flame is sensed through the ignition
module’s flame sensing rod. If pilot flame is not sensed, the
ignitor remains energized, and pilot gas valve remains open.
If this is due to a gas interruption, the system continues its
attempt to light pilot until gas is restored and unit lights or
system is turned off. When pilot flame is sensed, the main
gas valve opens and the pilot flame lights the burners. The
blower on delay period then begins.

5. Blower on delay—The fan control starts blower after 30
sec. The blower on delay is not adjustable.

6. Blower off delay—When thermostat is satisfied, the circuit
between R and W is broken, de-energizing gas valve and
stopping gas flow to burners. The blower motor remains
energized 60, 90, 120, or 150 sec depending on blower off
delay selection (factory shipped set for 60-sec delay).

7. Post purge—Inducer motor remains energized for 5 sec
after burners are extinguished.

II. COOLING MODE

When wall thermostat calls for cooling, the R-G and R-Y circuits
close. The R-Y circuit starts outdoor condensing unit, and the
combined R-Y and R-G circuits start furnace blower motor on
cooling speed.

When thermostat is satisfied, the R-G and R-Y circuits are broken.
The furnace blower de-energizes immediately.

START-UP, ADJUSTMENT, AND SAFETY CHECK

I. GENERAL

1. The furnace must have a 115-v power supply properly
connected and grounded.

NOTE: Proper polarity must be maintained for correct operation.

2. Thermostat wire connections at R, W, Y, and C must be
made at the 24-v terminal block on control board.

3. The gas service pressure must not exceed 0.5 psig (14-in.
wc), but must be no less than 0.16 psig (4.5-in. wc) for
natural gas.

II. REMOVE SHIPPING BRACKET

The furnace is equipped with a metal blower wheel shipping
bracket which MUST be removed before putting furnace into
operation. To remove this bracket:

1. Remove blower access panel.

2. Remove 2 mounting screws.

3. Slide bracket off blower wheel hub.

4. Replace blower panel.

III. PURGE GAS LINES

If not previously done, purge the lines after all connections have
been made and check for leaks.

WARNING: Never purge a line into a combustion
chamber. Never use matches, candles, flame, or other
sources of ignition for the purpose of checking leakage.
Use a soap-and-water solution to check for leakage.
Failure to follow this warning could result in a fire,
explosion, personal injury, or death.

CAUTION: Many soaps used for leak testing are corro­sive to certain metals. Piping must be rinsed thoroughly
with clean water after leak check has been completed.

IV. OPERATIONAL CHECKOUT

This furnace is equipped with an automatic hot surface pilot
ignition control and does not require lighting of a pilot for furnace
operation.

WARNING: Do not attempt to manually light pilot.
Failure to follow this warning can lead to electrical shock
which could result in bodily harm.

The automatic gas valve controls the flow of gas to both the pilot

→

and main burners. The manual switch built into automatic valve
body has 2 positions: OFF and ON.

→

To shut off gas manually, turn switch from ON to OFF position.
When in OFF position, main burners and pilot are extinguished.

After duct work connections have been made, gas piping and
electrical wiring completed, and furnace had been properly vented,
unit should be started and adjusted for proper operation. Check off
the following items as they are completed.

1. Make sure all electrical power is off.

2. Check all wiring using proper wiring diagram on inside of
control box cover.

3. Turn on electrical power to unit.

4. Turn gas valve manual switch to ON position.

→

5. Set thermostat above room temperature.

6. The hot surface ignitor should heat up to an orange glow
and ignite pilot. If flame sensor detects a proper flame, main
burners will ignite. If main burners do not ignite, see Adjust
Pilot Flame section below.

7. When main burners ignite, proceed to Set Gas Input Rate
section.

—13—

V. ADJUSTMENTS
A. Adjust Pilot Flame

Pilot assembly should be located as shown in Fig. 13. Adjust pilot
flame to envelop the flame sensor for a distance of 3/8 to 1/2 in.
(See Fig. 14.) The adjusting screw for pilot flame is located on
main gas control. (See Fig. 15.)

A96078

Fig. 13—Position of Pilot Assembly to Burner

d. Find natural gas heat value and specific gravity in Table

5.

e. Follow heat value line and specific gravity line to point

of intersection to find orifice size and manifold pressure
settings for proper operation at given natural gas condi­tion.

f. Check and verify orifice size in furnace. NEVER AS-

SUME THE ORIFICE SIZE. ALWAYS CHECK AND
VERIFY.

EXAMPLE:
Heat value = 1025 Btu/cu ft
Specific gravity = 0.62.
Therefore: Orifice No. 40 or 41*

Manifold Pressure 3.3 or 3.5 in. wc
* The furnace is shipped with No. 42 orifices. In this
example all main burner orifices must be changed and
manifold pressure must be adjusted.

3

⁄8″ TO 1⁄2″

FLAME
SENSING
ROD

HOT
SURFACE
IGNITOR

A96077

Fig. 14—Position of Pilot Flame to Flame Sensor

B. Set Gas Input Rate

WARNING: Never set furnace input rate above that

shown on rating plate. Failure to follow this warning
could lead to premature heat exchanger failure and a
hazardous furnace operating condition and result in
serious bodily injury or loss of life.

There are 2 methods of adjusting gas input rate. The preferred
method is by using Table 5 and item 1. The second method is by
clocking the gas meter and using item 2. Item 2 must be used for
altitudes above 2000 ft.

1. Determine natural gas orifice size and manifold pressure for
correct input using Table 5.

a. Obtain average yearly heat value for local gas supply.
b. Obtain average yearly specific gravity for local gas

supply.

c. Verify the furnace model. Table 5 can only be used for

model 349HAV Furnaces.

g. Proceed to item 3 to adjust manifold pressure.

2. Determine natural gas input rate by clocking gas meter.

NOTE: Be sure all pressure tubing, vent pipes, and burner
enclosure plates are in place when checking input.

a. Obtain average yearly heat value for local gas supply.

NOTE: Be sure heating value of gas used for calculations is
correct for your altitude. Consult local gas utility for altitude
adjustments of gas heating value.

b. Turn off all other gas appliances and pilots.
c. Start furnace and let it run for 3 minutes.
d. Measure time (in sec) for gas meter test dial to complete

1 revolution.
e. Refer to Table 6 for cu ft of gas per hr.
f. Multiply gas rate (cu ft/hr) by heating value (Btu/cu ft).

Obtain heating value from local gas utility.

EXAMPLE:
Btu heating input = Btu/cu ft X cu ft/hr
Heating value of gas = 1070 Btu/cu ft
Time for 1 revolution of 2-cu-ft dial = 72 sec
Gas rate = 100 cu ft/hr (from Table 6)
Btu heating input = 100 X 1070 = 107,000 Btuh.

g. Measured gas input must not exceed gas input on unit

rating plate.

(1.) High-altitude installations (United States

only)—Gas input on rating plate is for altitudes up
to 2000 ft. Ratings for altitudes over 2000 ft must be
4 percent less for each 1000 ft above sea level. To
obtain the altitude adjusted rating, adjust the mani­fold pressure (see item 3), and replace the main
burner orifices as needed (see item 4). Refer to
NFGC Appendix F, Table F-4 for proper orifice
sizing at high altitudes.

(2.) High-altitude installations (Canada only)—The Ca-

nadian ratings are approved for altitudes up to 2000
ft for natural and propane gases. High-altitude
ratings are from 2000 ft to 4500 ft above sea level.
See Table 7 for nominal burner orifice size. High­altitude input ratings include a 10 percent derate as
required by Canadian standards.

h. Proceed to item 3 to adjust manifold pressure.

—14—

TABLE 5—MODEL 349HAV ORIFICE SIZE AND MANIFOLD PRESSURE FOR CORRECT INPUT RATE

(TABULATED DATA BASED ON ALTITUDES UP TO 2000 FT AND 25,000 BTUH PER BURNER)

GAS HEAT SPECIFIC GRAVITY OF NATURAL GAS

VALUE 0.56 0.58 0.60 0.62 0.64 0.66 0.68 0.70 0.72

Orf.

Mnfld

Orf.

Mnfld

Orf.

(Btu/cu ft)

860

875

890

905

920

935

950

965

980

995

1010

1025

1040

1055

1070

1085

1100

No.

37
38

—

37
38
39

38
39

—

38
39
40

38
39
40

39
40
41

39
40
41

40
41

—

40
41

—

41
42

—

41
42

—

41
42

—

42

—
—

42
—
—

42
—
—

42
—
—

43
—
—

Press

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.4

3.7

3.3

3.5

3.8

3.2

3.4

3.7

3.3

3.6
—

3.2

3.5
—

3.4

3.8
—

3.3

3.7
—

3.2

3.6
—

3.4
—
—

3.4
—
—

3.3
—
—

3.2
—
—

3.8
—
—

No.

37
38
—

37
38
—

37
38
39

38
39
—

38
39
40

38
39
40

39
40
—

39
40
41

40
41
—

40
41
—

41
42
—

41
42
—

41
42
—

42
—
—

42

—
—

42

—
—

42

—
—

Press

3.4

3.8
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.4

3.7

3.3

3.6
—

3.2

3.4

3.7

3.3

3.6
—

3.2

3.5
—

3.4

3.8
—

3.3

3.7
—

3.2

3.6
—

3.5
—
—

3.4
—
—

3.3
—
—

3.2
—
—

No.

36
37

—

37
38

—

37
38

—

37
38
39

38
39

—

38
39
40

38
39
40

39
40

—
39

40
41

40
41
—

40
41
—

40
41
42

41
42
—

41
42
—

42
—
—

42
—
—

42
—
—

Mnfld
Press

3.2

3.5
—

3.4

3.8
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.5

3.7

3.3

3.6
—

3.2

3.5

3.7

3.4

3.6
—

3.3

3.5
—

3.2

3.4

3.8

3.3

3.7
—

3.2

3.6
—

3.5
—
—

3.4
—
—

3.3
—
—

Orf.
No.

36
37
—

36
37
—

37
38
—

37
38
—

37
38
39

38
39
—

38
39
40

38
39
40

39
40
—

39
40
41

39
40
41

40
41
—

40
41
42

41
42
—

41
42
—

41
42
—

42
—
—

Mnfld
Press

3.3

3.7
—

3.2

3.5
—

3.4

3.8
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.5

3.7

3.4

3.6
—

3.3

3.5

3.8

3.2

3.4

3.6

3.3

3.5
—

3.2

3.4

3.8

3.3

3.7
—

3.2

3.6
—

3.2

3.5
—

3.4
—
—

Orf.

No.

36
37

—

36
37

—

36
37

—

37
38

—

37
38

—

37
38
39

38
39

—

38
39
40

38
39
40

39
40

—

39
40
41

39
40
41

40
41

—

40
41
42

41
42
—

41
42
—

41
42
—

Mnfld
Press

3.4

3.8
—

3.3

3.6
—

3.2

3.5
—

3.4

3.8
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.5

3.7

3.4

3.6
—

3.3

3.5

3.8

3.2

3.4

3.7

3.3

3.6
—

3.2

3.4

3.8

3.4

3.7
—

3.3

3.6
—

3.2

3.5
—

Orf.
No.

36
—
—

36
37
—

36
37
—

36
37
—

37
38
—

37
38
—

37
38
39

38
39
—

38
39
40

38
39
40

39
40
—

39
40
41

39
40
41

40
41
—

40
41
42

41
42
—

41
42
—

Mnfld
Press

3.5
—
—

3.4

3.8
—

3.3

3.6
—

3.2

3.5
—

3.4

3.7
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.5

3.7

3.4

3.6
—

3.3

3.5

3.8

3.2

3.4

3.7

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6
—

Orf.
No.

35
36
—

36
—
—

36
37
—

36
37
—

36
37
—

37
38
—

37
38
—

37
38
39

38
39
—

38
39
40

38
39
40

39
40
—

39
40
41

39
40
41

40
41
—

40
41
42

41
42
—

Mnfld
Press

3.2

3.6
—

3.5
—
—

3.4

3.7
—

3.3

3.6
—

3.2

3.5
—

3.4

3.7
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.5

3.7

3.4

3.6
—

3.3

3.5

3.8

3.2

3.4

3.7

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

Orf.
No.

34
35
36

35
36
—

36
—
—

36
37
—

36
37
—

36
37
38

37
38
—

37
38
—

37
38
39

38
39
—

38
39
40

38
39
40

39
40
—

39
40
41

39
40
41

40
41

—

40
41

—

Mnfld
Press

3.2

3.3

3.7

3.2

3.6
—

3.5
—
—

3.4

3.7
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.5

3.7

3.4

3.6
—

3.3

3.5

3.8

3.2

3.4

3.7

3.3

3.6
—

3.2

3.5
—

Orf.
No.

34
35
—

34
35
36

35
36
—

36
37
—

36
37
—

36
37
—

36
37
38

37
38
—

37
38
—

37
38
39

38
39
—

38
39
40

38
39
40

39
40
—

39
40
41

39
40
41

40
41

—

Mnfld
Press

3.3

3.4
—

3.2

3.3

3.7

3.2

3.6
—

3.5

3.8
—

3.4

3.7
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6
—

3.2

3.5

3.8

3.4

3.7
—

3.3

3.6

3.8

3.2

3.5

3.7

3.4

3.6
—

3.3

3.5

3.8

3.2

3.4

3.7

3.3

3.6
—

—15—

SECONDS

FOR 1

REVOLUTION

10
11
12
13
14
15
16
17
18

19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49

TABLE 6—GAS RATE CU FT/HR

1800
1636
1500
1385
1286
1200
1125
1059

10 0

947
900
857
818
783
750
720
692
667
643
621
600
581
563
545
529
514
500
486
474
462
450
439
429
419
409
400
391
383
375
367

SECONDS

FOR 1

REVOLUTION

50
51
52
53
54
55
56
57
58
59
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96

98
100
102
104
106
108

110
112
116
120

SIZE OF TEST DIAL

1

cu ft2cu ft5cu ft

72
71
69
68
67
65
64
63
62
61
60
58
56
54
53
51
50
48
47
46
45
44
43
42
41
40
39
38
38
37
36
35
35
34
33
33
32
31
30

SIZE OF TEST DIAL

1

cu ft2cu ft5cu ft

360

720

327

655

300

600

277

555

257

514

240

480

225

450

212

424

200

400

189

379

180

360

171

343

164

327

157

313

150

300

144

288

138

277

133

267

129

257

124

248

120

240

116

232

113

225

109

218

106

212

103

206

100

200

97

195

95

189

92

185

90

180

88

176

86

172

84

167

82

164

80

160

78

157

76

153

75

150

73

147

144
141
138
136
133
131
129
126
124
122
120
116
112
109
106
103
100

97
95
92
90
88
86
84
82
80
78
76
75
74
72
71
69
68
67
65
64
62
60

360
355
346
340
333
327
321
316
310
305
300
290
281
273
265
257
250
243
237
231
225
220
214
209
205
200
196
192
188
184
180
178
173
170
167
164
161
155
150

IGNITOR

CONNECTOR

IGNITION SYSTEM
CONTROL SWITCH

IGNITION
MODULE

PILOT

ADJUSTMENT

(UNDER CAP

SCREW)

PILOT

OUTLET

INLET
PRESSURE
TAP

GAS
PRESSURE
REGULATOR

MANIFOLD

PRESSURE

TAP

ADJUSTMENT
(UNDER CAP
SCREW)

→ Fig. 15—Honeywell SmartValve

d. Replace cap that conceals gas valve regulator adjustment

screw.

CAUTION: Be sure burner enclosure front is in place
after adjustments have been made.

e. Look through openings in burner enclosure and check

burner flame. The main burner flame should be clear
blue, almost transparent. (See Fig. 16.)

BURNER FLAMEPILOT FLAME

A98304

TABLE 7—CANADIAN ORIFICE SIZE

GAS

SEA LEVEL

0-2000 FT

Natural 42 43

Propane 54 55

HIGH ALTITUDE

2000-4500 FT

3. Adjust gas input.

NOTE: The gas valve has been nominally set at 3.5-in. wc for
natural gas.

a. Remove cap that conceals adjustment screw for gas

valve regulator. (See Fig. 15.)

b. Turn adjusting screw either counterclockwise (out) to

decrease input rate or clockwise (in) to increase rate.
When adjusting input rate, DO NOT set manifold
pressure less than 3.2-or more than 3.8-in. wc for natural
gas. Make any major adjustments by changing main
burner orifices.

WARNING: DO NOT redrill orifices. Improper drilling
(burrs, out-of-round holes, etc.) can cause excessive
burner noise and misdirection of burner flames. This can
result in flame impingement of the burners and heat
exchangers causing failures.

NOTE: If orifice hole appears damaged or it is suspected to have
been redrilled, check the orifice hole with the correct size
numbered drill bit. Never redrill an orifice. A burr-free and
squarely aligned orifice hole is essential for proper flame charac­teristics.

c. Measure adjusted gas input rate using method outlined in

item 2.

BURNER

MANIFOLD

A84076

Fig. 16—Pilot and Burner Flames

4. Change burner orifice (if necessary).
The furnace is supplied with standard orifices for the gas

shown on rating plate. If orifices need to be changed to
achieve proper input rate, proceed as follows:

a. Remove manifold pipe cover and burner removal

cover/air inlet plate.
b. Remove manifold retention plate.
c. Pull manifold/burner assembly out past support pins and

remove assembly.

—16—

NOTE: It is only necessary to remove 1 manifold retention plate
to gain access to burners.

d. Remove burners from assembly and change orifices as

required.

e. Reinstall assembly by reversing the procedure in items a

through d making sure that assembly is securely
mounted under manifold retention plate on opposite side
of unit.

CAUTION: Care must be taken when removing pilot
burner in order not to damage pilot gas line or hot surface
ignitor.

f. After securing manifold assembly, replace all other

components and/or wiring making sure that all connec­tions and screws are tightened properly.

C. Set Temperature Rise

The furnace must not be operated outside the range of temperature
rise specified on unit rating plate. Determine air temperature rise as
follows:

a. Place thermometers in return and supply ducts as near

furnace as possible. Be sure thermometers do not "see"
heat exchanger so that radiant heat does not affect
readings. This practice is particularly important with
straight-run ducts.

b. When thermometer readings stabilize, subtract return-air

temperature from supply-air temperature to determine
air temperature rise.

c. Adjust temperature rise by adjusting blower speed.

Increase blower speed to reduce temperature rise. De­crease blower speed to increase temperature rise.

WARNING: Disconnect the electrical power before
changing the speed tap. Failure to follow this warning
could result in personal injury.

d. To change motor speed taps, remove the motor tap lead

and relocate it on the desired terminal on the plug in
terminal block/speed selector located at the blower
motor. (See Table 8.)

TABLE 8—BLOWER SPEED SELECTION

SPEED TAP NO.

Common 1

High 2

Medium 3

Low 4

CAUTION: Recheck the temperature rise. It must be

within limits specified on the unit rating plate. Recom­mended operation is at midpoint of rise or above.

D. Set Blower Off Delay

The blower off delay may be adjusted for a 60- (factory setting),
90-, 120-, or 150-sec delay. Set the DIP switches on the control
board to obtain desired time delay. (See Fig. 17.)

E. Set Thermostat Heat Anticipator

The thermostat heat anticipator must be set to match the amp draw
of components in the R to W circuit. Accurate amp draw
measurements can be obtained at thermostat subbase terminals R
and W.

12

60 Sec

DELAY OFF DIP SWITCH SETTINGS

12

12 1212

90 Sec

120 Sec

12

150 Sec

A95115

Fig. 17—Blower Off Delay Settings

THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
(ANITICIPATOR, CLOCK, ETC.,
MUST BE OUT OF CIRCUIT.)

HOOK-AROUND
AMMETER

R Y W G

10 TURNS

FROM UNIT 24-V
CONTROL TERMINALS

EXAMPLE:

5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS

0.5 AMPS FOR THERMOSTAT

=

ANTICIPATOR SETTING

A96316

Fig. 18—Amp Draw Check with Ammeter

Fig. 18 illustrates an easy method of obtaining these measure­ments. The amp reading should be taken after blower motor has
started. See thermostat manufacturer’s instructions for adjusting
heat anticipator and for varying heating cycle length.

VI. CHECK SAFETY CONTROLS
A. Check Primary Limit Control

The heat sensing switch performs as the furnace high temperature
limit switch. If furnace overheats for any reason, the limit switch
opens, breaking circuit to main gas valve. If limit is activated
check for a restriction in duct system (dirty filters, blocked duct
work, closed registers, etc.). The blower motor is energized and as
unit cools, limit switch closes. This relights main burners, but
unless overheating condition is corrected, furnace will cycle on
limit. Corrective action must be taken.

The recommended method of checking limit control is to gradually
block off return air after furnace has been operating for a period of
at least 5 minutes. As soon as limit control has shut off burners,
return-air opening should be unblocked to permit normal air
circulation. By using this method to check limit control, it can be
established that limit is functioning properly and will operate if
there is a restricted circulating air supply or motor failure. If limit
control does not function during this test, the cause must be
determined and corrected.

B. Check Pressure Switch (Blocked-Vent Shutoff
Switch)

This control proves operation of the draft inducer. Check switch
operation as follows:

1. Turn off 115-v power to furnace.

2. Remove control box cover and disconnect inducer motor
lead wires from control board.

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3. Turn on 115-v power to furnace.

4. Set thermostat to call for heat. When pressure switch is
functioning properly, ignitor should not glow. If ignitor
glows when inducer motor is disconnected, shut down
furnace immediately. Determine the reason pressure switch
did not function properly and correct the condition.

5. Turn off 115-v power to furnace.

6. Reconnect inducer motor lead, reinstall control box cover,
and turn on 115-v power supply.

C. Flame Rollout Switch

This furnace is equipped with a manual reset flame rollout shutoff
switch which is attached to burner/manifold assembly. In the event
that a blockage prevents venting of flue gases from heat exchanger,
the switch detects conditions that would produce a flame rollout

and shuts off power to automatic gas valve before there is furnace
damage or a flame rollout outside of furnace cabinet. The loss of
power to gas valve shuts off gas burners, however, blower is still
controlled by fan and limit switch and operates until heat ex­changer temperatures have cooled.

CHECKLIST

1. Put away tools and instruments. Clean up debris. Verify that
blower and control access panels are properly installed.

2. Cycle test furnace with room thermostat.

3. Check operation of accessories per manufacturer’s instruc­tions.

4. Review User’s Guide with owner.

5. Leave literature packet near furnace.

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SERVICE TRAINING

Packaged Service Training programs are an excellent way to increase your
knowledge of the equipment discussed in this manual, including:
 • Unit Familiarization • Maintenance
 • Installation Overview • Operating Sequence
A large selection of product, theory, and skills programs is available, using popular
video-based formats and materials. All include video and/or slides, plus companion
book.

Classroom Service Training plus "hands-on" the products in our labs can mean
increased confidence that really pays dividends in faster troubleshooting, fewer
callbacks. Course descriptions and schedules are in our catalog.


CALL FOR FREE CATALOG 1-800-962-9212



[ ] Packaged Service Training [ ] Classroom Service Training

A94328

© 1998 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231

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Printed in U.S.A. 349h505 Catalog No. 5334-900