Bryant 333BAV User Manual

service and

333BAV

maintenance procedures

UPFLOW/HORIZONTAL,
VARIABLE-SPEED, 2-STAGE,
INDUCED-COMBUSTION FURNACES

NOTE: Read the entire instruction manual before performing any
service or maintenance.

This symbol → indicates a change since the last issue.
These procedures are for size 60,000 through 120,000 Btuh units.
Index Page

SAFETY CONSIDERATIONS.....................................................1

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

PROCEDURE...........................................................................2

CARE AND MAINTENANCE..................................................2-5

Air Filter Arrangement..........................................................2-3

Blower Motor and Wheel.........................................................3

Cleaning Heat Exchanger......................................................3-5

Electrical Controls and Wiring.................................................5

Troubleshooting ........................................................................5

Application Wiring Diagrams ..................................................6

Unit Wiring Diagram................................................................7

Service Label ............................................................................8

Troubleshooting Guide .............................................................9

333JAV

Series B

Cancels: SP04-43 SP04-50

10-97

A95137

Fig. 1—Model 333BAV or 333JAV Horizontal

®

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, tags, and
labels attached to or shipped with the 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 NFPA No. 54­1996/ANSI Z223.1-1996. In Canada, refer to the current edition of
the National Standard of Canada CAN/CGA-B149.1- and .2-M95
Natural Gas and Propane Gas Installation Codes. 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

A94085

CERTIFICATION OF
MANUFACTURING SITE

.

WARNING: The ability to properly perform mainte­nance on this equipment requires certain expertise, me­chanical skills, tools, and equipment. If you do not
possess these items, do not attempt to perform any
maintenance on this equipment other than those proce­dures recommended in the User’s Manual. A FAILURE
TO FOLLOW THIS WARNING COULD RESULT IN
POSSIBLE DAMAGE TO THIS EQUIPMENT, SERI­OUS PERSONAL INJURY, OR DEATH.

Fig. 2—Model 333BAV or

333JAV Upflow

—1—

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

PROCEDURE

CAUTION: Electrostatic discharge can affect electronic

components. Take precautions during furnace installation
and servicing to protect the furnace electronic control and
motor. 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, the motor, and the person at the same
electrostatic potential.

WARNING: Turn off the gas and electrical supplies to
the unit before performing any maintenance or service on
it. Follow the operating instructions on the label attached
to the furnace. A failure to follow this warning could
result in personal injury.

CAUTION: As with any mechanical equipment, per­sonal injury can result from sharp metal edges, etc.;
therefore, be careful when removing parts.

1. Disconnect all power to the furnace. DO NOT TOUCH

THE CONTROLS OR ANY WIRE CONNECTED TO
THE CONTROLS 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 controls. Tools held in
a person’s hand during grounding will be satisfactorily
discharged.

3. After touching the chassis you may proceed to service the
controls, motor, 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 ungrounded objects, etc.).

4. If you touch ungrounded objects (recharge your body with
static electricity), firmly touch furnace again before touch­ing control or wires.

5. Use this procedure for installed and uninstalled (un­grounded) furnaces.

6. Before removing a new control or motor from its container,
discharge your body’s electrostatic charge to ground to
protect the control or motor from damage. If the control or
motor is to be installed in a furnace, follow items 1 through
5 before bringing the control, or motor, or yourself into
contact with the furnace. Put all used AND new controls
and motors into containers before touching ungrounded
objects.

The minimum maintenance that should be performed on this
equipment is as follows:

1. Check and clean air filter each month or more frequently if
required. Replace if torn.

2. Check blower motor and wheel for cleanliness each heating
and cooling season. Clean as necessary.

3. Check electrical connections for tightness and controls for
proper operation each heating season. Service as necessary.

CAUTION: If motor is removed from blower assembly,
the motor MUST be reinstalled so arrow on end of the
motor is pointing in the direction of airflow through the
furnace. The belly band MUST be the specified distance
from the motor end shield surface at the shaft end. (See
Fig. 3.)

D

7. An ESD service kit (available from commercial sources)
may also be used to prevent ESD damage.

CARE AND MAINTENANCE

For continuing high performance and to minimize possible equip­ment failure, it is essential that periodic maintenance be performed
on this equipment. Consult your local dealer as to the proper
frequency of maintenance and the availability of a maintenance
contract.

WARNING: Never store anything on, near, or in contact
with the furnace, such as: 1. Spray or aerosol cans, rags,
brooms, dust mops, vacuum cleaners, or other cleaning

tools.

2. Soap powders, bleaches, waxes or other cleaning
compounds, plastic or plastic containers, gasoline, kero-

sene, cigarette lighter fluid, dry cleaning fluids, or other
volatile fluids.

3. Paint thinners and other painting compounds, paper
bags or other paper products.
A failure to follow this warning could result in corrosion
of the heat exchanger, fire, personal injury, or death.

A95268

DIMENSIONS (IN.)

FURNACE SIZE D

036060 1
048080 1-1/2
060100 3
060120 3

Fig. 3—Motor Belly Band Location

A. Air Filter Arrangement

The air filter arrangement may vary depending on the application.
Refer to Table 1 for filter size information.

WARNING: Never operate unit without a filter or with
filter access door removed. A failure to follow this
warning could result in fire, personal injury, or death.

1. Upflow and horizontal.
Each furnace requires 1 or 2 filters which are installed in the
blower compartment. (See Fig. 4.) To remove filters for
cleaning or replacement, proceed as follows:

—2—

TABLE 1—UPFLOW/HORIZONTAL FILTER SIZE INFOR-

MATION (IN.)

FURNACE

CASING WIDTH

14-3/16 (1) 16 X 25 X 1* (1) 14 X 25 X 1 Cleanable

21 (1) 16 X 25 X 1 (1) 20 X 25 X 1* Cleanable

24-1/2 (2) 16 X 25 X 1* (1) 24 X 25 X 1 Cleanable

* Factory-provided with the furnace.
† Filters may be field modified as required by cutting and folding the frame as
indicated on the filter.

FILTER SIZE†

Side Return Bottom Return

FILTER

TYPE

a. Turn off electrical supply before removing blower and

control access doors.

b. Release filter retainer from clip at front of furnace

casing. (See Fig. 4.) For side return, clips may be used
on either or both sides of the furnace.

MOUNTING

SCREWS

DRAFT
SAFEGUARD
SWITCH

Clean as follows:

1. Remove blower access door.

2. Disconnect blower electrical leads from motor. Squeeze
latches to remove connectors from motor. Disconnect green
ground wire from screw. Note location of wires for reas­sembly.

3. Remove control.

4. Remove screws holding blower assembly to blower deck
and slide blower assembly out of furnace.

5. Mark blower wheel, motor, and motor support in relation to
blower housing before disassembly to ensure proper reas­sembly.

6. Loosen setscrew(s) holding blower wheel on motor shaft.

7. Remove bolts holding motor and motor mount to blower
housing and slide motor and mount out of housing. Motor
mount belly band need not be removed unless motor is to be
replaced.

RELIEF

BOX
MAIN

LIMIT

SWITCH

MANUAL

RESET

LIMIT

SWITCHES

AIRFLOW

SELECTOR

CONTROL

PRESSURE
SWITCHES

WASHABLE
FILTER

FILTER
RETAINER

A95270

Fig. 4—Upflow/Horizontal Component Identification

c. Slide filter out.
d. Clean filters by spraying tap water through filter from

opposite direction of airflow.

e. Rinse and let dry. Oiling or coating of filter is not

recommended or required.
f. Place filter in furnace.
g. Replace blower and control access doors and turn on

electrical supply to furnace.

B. Blower Motor and Wheel

For long life, economy, and high efficiency, clean accumulated dirt
and grease from the blower wheel and motor annually.

The following steps should be performed by a qualified service
technician:

The motors have prelubricated sealed bearings and require no
lubrication.

Remember to disconnect the electrical supply before removing
access doors.

CAUTION: The blower wheel should not be dropped or
bent as balance will be affected.

8. Remove blower wheel from housing.
a. Mark cutoff plate location to ensure proper reassembly.

b. Remove screws holding cutoff plate and remove cutoff

plate from housing.

c. Lift blower wheel from housing through opening.

9. Clean blower wheel and motor using a vacuum with soft
brush attachment. Do not remove or disturb balance weights
(clips) on blower wheel blades.

10. Reinstall blower wheel by reversing items 8 a through c. Be
sure wheel is positioned for proper rotation.

11. Reassemble motor and blower by reversing items 4 through

7.

CAUTION: Be sure the motor is properly positioned in
the blower housing. The motor arrow must point in the
direction of airflow through the furnace after the blower
assembly has been reinstalled in the furnace.

12. Reinstall blower assembly in furnace.

13. Reinstall control. If motor has ground wire, be sure it is
connected as before.

14. Connect blower electrical leads to motor. Please note that
connections are polarized for assembly. DO NOT FORCE.

15. If power choke is attached to blower housing, ensure it is
connected in series with black power lead to motor.

C. Cleaning Heat Exchanger

The following steps should be performed by a qualified service
technician:

NOTE: Deposits of soot and carbon indicate the existence of a
problem which needs to be corrected. Take action to correct the
problem.

If it becomes necessary to clean the heat exchanger because of
carbon deposits, soot, etc., proceed as follows:

1. Turn gas and power to furnace to OFF.

2. Remove control and blower access doors.

3. Disconnect wires to the following components. Mark wires
to aid in reconnection of:

—3—

a. Draft safeguard switch.
b. Inducer motor.
c. Pressure switch(es).
d. Limit overtemperature switch(es).
e. Gas valve.
f. Hot surface ignitor.
g. Flame-sensing electrode.
h. Wiring connectors leading to control.

4. Remove 2 screws that secure relief box. (See Fig. 4.)

5. Remove 8 screws that secure flue collector box to center
panel. Be careful not to damage sealant.

6. Remove complete inducer assembly from furnace, exposing
flue openings.

7. Using field-provided small wire brush, steel spring cable,
reversible electric drill, and vacuum cleaner, clean cells as
follows:

a. Assemble wire brush and steel spring cable.

(1.) Use 48 in. of 1/4-in. diameter high-grade steel

spring cable (commonly known as drain clean-out
or Roto-Rooter cable).

(2.) Use 1/4-in. diameter wire brush (commonly known

as 25-caliber rifle cleaning brush).

NOTE: The materials needed in items (1.) and (2.) can usually be
purchased at local hardware stores.

(3.) Insert twisted wire end of brush into end of spring

cable, and crimp tight with crimping tool or strike
with ball-peen hammer. TIGHTNESS IS VERY
IMPORTANT.

(4.) Remove metal screw fitting from wire brush to

allow insertion into cable.

b. Clean each heat exchanger cell.

(1.) Attach variable-speed, reversible drill to end of

spring cable (end opposite brush).

(2.) Remove cell outlet plates. IMPORTANT: Replace

screws in center panel to secure heat exchanger
cells before cleaning.

(3.) Insert brush end of cable into upper opening of cell

and slowly rotate with drill. DO NOT force cable.
Gradually insert at least 36 in. of cable into 2 upper
passes of cell. (See Fig. 5.)

A91252

Fig. 5—Cleaning Heat Exchanger Cell

(4.) Work cable in and out of cell 3 or 4 times to obtain

sufficient cleaning. DO NOT pull cable with great
force. Reverse drill and gradually work cable out.

(5.) Remove burner assembly and cell inlet plates.

NOTE: Be very careful when removing the burner assembly to
avoid breaking the ignitor. See Fig. 6 for the correct ignitor
location.

13

32

BURNER

"

Fig. 6—Position of Ignitor to Burner

11

CELL
PANEL

HOT
SURFACE
IGNITOR
ASSEMBLY

C

IGNITOR

L

7

8

"

C

BURNER

L

IGNITOR
ASSEMBLY

32

"

A93347

(6.) IMPORTANT: Replace screws in center panel to

secure heat exchanger cells before cleaning.

(7.) Insert brush end of cable in lower opening of cell,

and proceed to clean 2 lower passes of cell in same
manner as 2 upper passes.

(8.) Repeat foregoing procedures until each cell in

furnace has been cleaned.

(9.) Using vacuum cleaner, remove residue from each

cell.

(10.) Using vacuum cleaner with soft brush attachment,

clean burner assembly.

(11.) Reinstall cell outlet plates and screws FIRST;

then, reinstall cell inlet plates and burner assem­bly. Care must be exercised to center the burners
in the cell openings.

8. After cleaning flue openings, clean flue collector. Check
sealant on flue collector to ensure that it has not been
damaged. If new sealant is needed, contact your dealer or
distributor.

9. Replace flue collector assembly, making sure all 8 screws
are secure.

10. Reinstall relief box.

11. Reconnect wires to the following components:
a. Draft safeguard switch.

b. Inducer motor.
c. Pressure switches.
d. Limit overtemperature switch(es).
e. Gas valve.
f. Hot surface ignitor.

—4—

g. Flame-sensing electrode.
h. Wiring connectors leading to control.

12. Reconnect vent pipe to relief box.

13. Replace blower door only.

14. Turn power and gas to ON.

15. Set thermostat and check furnace for proper operation.

16. Verify blower airflow and that airflow rate changes between
heating and cooling.

17. Check for gas leaks.

18. Replace control door.

WARNING: Never use a match or other open flame to
check for gas leaks. Use a soap-and-water solution. A
failure to follow this warning could result in fire, personal
injury, or death.

D. Electrical Controls and Wiring
NOTE: There may be more than 1 electrical supply to unit.

The electrical ground and polarity for 115-v wiring must be
maintained properly. Refer to Fig. 7 and 8 for field wiring
information and to Fig. 9 for unit wiring information. If the
polarity is NOT correct, the furnace control will display rapid
flashing on the status LED and prevent heat operation. The control
system also requires an earth ground for proper operation of the
microprocessor and variable-speed motor.

NOTE: Be aware that measurement of current (amperes) and
power (watts) for the ICM2+ variable-speed motor will be accurate
only when the meter provides true root-mean-square (RMS)
measurements.

With power disconnected from unit, check all electrical connec­tions for tightness. Tighten all screws on electrical connections. If
any smoky or burned connections are noticed, disassemble the
connection, clean all parts and stripped wire, and reassemble
properly and securely. Electrical controls are difficult to check
without proper instrumentation; therefore, reconnect electrical
power to unit and observe unit through 1 complete operating cycle.

The 24-v circuit contains an automotive-type, 3-amp fuse located
on the main control. Any 24-v electrical shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3-amp fuse. The control will
display code 24 when the fuse needs replacement.

The control in this furnace is equipped with an LED status light to
aid in installation, servicing, and troubleshooting. It can be viewed
through the sight glass or window on the blower access door. The
control indicates status with the LED on continuously, rapid
flashing, or a code composed of 2 digits. (The first digit is the
number of short flashes, the second is the number of longs flashes.)
Refer to the service label on the blower compartment door for code
explanations and useful troubleshooting suggestions. (See Fig. 10.)

It is important to note that power to the furnace must not be
interrupted and the furnace blower door must not be removed until
the LED status code(es) is recorded. When power to the control is
interrupted, the status memory is erased.

The control will store up to 5 previous codes but will not store
non-current codes longer than 48 hr. To retrieve previous codes, if
present, no thermostat inputs to the control must be present and all
time delays must expire. Remove 1 of the red main limit wires 1
to 4 sec until the LED light goes out, then reconnect it. (See Fig.

4.) (Do not leave red wire disconnected for longer than 4 sec as the
control will assume an overtemperature condition exits and will
respond with indoor blower operation.) This places the control in
the status recall mode and displays the first code stored in memory.
Record the code and repeat the disconnect and reconnect of the red
wire, recording each code until code 11 is displayed indicating no
additional faults. After the last code is displayed or after 2 minutes
in the code recall mode, the control will return to normal standby
mode.

Use any recorded status codes, the service label, and the trouble­shooting diagram on the following pages to diagnose and correct
any problem condition.

E. Troubleshooting

Refer to the service label. (See Fig. 10.) Page 9 contains a
troubleshooting guide. This guide can be a useful tool in isolating
furnace operation problems. Beginning with the word "Start,"
answer each question and follow the appropriate arrow to the next
item.

The guide will help to identify the problem or failed component.
After replacing any component, verify correct operation sequence.
More information is available in a separate Troubleshooting Guide
for 2-stage gas-fired induced-combustion furnaces.

—5—

BLK

WHT

GND

115-V FIELD-

SUPPLIED

FUSED

DISCONNECT

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

FIVE

WIRE

THREE-WIRE

NOTE 2

WCY RG

1-STAGE
THERMOSTAT
TERMINALS

FIELD-SUPPLIED

FUSED DISCONNECT

HEATING-

ONLY

BLK

WHT

JUNCTION
BOX

CONTROL

BOX

AFS

FURNACE

W2

COM

W/W1

Y/Y2

R



G

24-V

TERMINAL

BLOCK

NOTE 5

NOTE 1

Y1

NOTES: 1.

O

CONDENSING

NOTE 4

UNIT

Connect Y/Y2-terminal as shown for proper operation.
Some thermostats require a "C" terminal connection as shown.

2.
If any of the original wire, as supplied, must be replaced, use

3.
same type or equivalent wire.



Y1 is not to be connected.

4.
Connect O to thermostat-O only for heat pump applications.

5.

→ Fig. 7—Heating and Cooling Application Wiring Diagram

for Single-Stage Thermostats and/or Single-Speed Condensing Units

208/230- OR
460-V
THREE
PHASE

208/230-V
SINGLE
PHASE

GND

A97588

BLK

WHT

GND

115-V FIELD-

SUPPLIED

FUSED

DISCONNECT

BLK

WHT

JUNCTION
BOX

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

SEVEN

WIRE

NOTE 2

W2 Y2 G Y1

 

W1CR

2-STAGE
THERMOSTAT
TERMINALS

FUSED DISCONNECT

FOUR-WIRE

HEATING-

ONLY

W2

COM

W/W1

CONTROL

AFS

FURNACE

BOX

24-V

TERMINAL

BLOCK

Y/Y2

GR

NOTE 4

NOTE 1

Y1

NOTES: 1.

Connect Y1 and Y/Y2 as shown for proper operation.
Some thermostats require a "C" terminal connection as shown.

2.
If any of the original wire, as supplied, must be replaced, use

3.
same type or equivalent wire.



Connect O to thermostat-O only for heat pump applications.

4.

C
Y1

Y2

2-SPEED
CONDENSING
UNIT

O

→ Fig. 8—Heating and Cooling Application Wiring Diagram

for 2-Stage Thermostats and/or 2-Speed Condensing Units

FIELD-SUPPLIED

208/230- OR
460-V
THREE
PHASE

208/230-V
SINGLE
PHASE

GND

A97589

—6—

FAN

-

LO

CFM

CONTINUOUS

GAS

HEAT

HI

HP

AC

CMFT

CFM

COOL

315

SIZE

COOL

3

Y1 6

seconds. The control will turn ON the inducer motor Low-Speed, inducer

motor High-Speed, HSI, blower motor Continuous-Fan Speed, blower

FIELD SPLICE

PLUG RECEPTACLE

322293-101 REV. C

AFS

NOTE 4

RISE

TEMP

PER

TON

4

7

O

Y1

motor High-Gas-Heat Speed, and blower motor High-Cool Speed for

7-15 seconds each. Neither the gas valve nor the humidifier will be

turned ON.

AIRFLOW SELECTOR JUMPER PINS

AIRFLOW SELECTOR FACTORY SETTING

A97587

→ Fig. 9—Unit Wiring Diagram

HSI

2

1

PL6

9

3

PL2

FU2

WHT

BLK

L1

L2

WHT

RED

PL6

12

GRY

WHT

NOTE 7

(WHEN USED)

ORN

RED

12

*

NORM

HI HT

LO HT

IDM

LS

USED)

(WHEN

LO

HI

COM

1

3

2

PL3

N/A

4

IHI / LOR

IDR

N/A

7

2

8

6

5

1

HPSR

PR2

SEC2

TRAN

24VAC

115VAC

PR1

SEC1

FU1

NOTE 6

(NATURAL GAS & PROPANE)

GRN

GRN

WHT
BLK

PL3

123

BLK

WHT

BLK

WHT

YEL

ALS1

ORN

OFF

4

ON
OFF

3

SWITCH

ON

90 SEC

BLOWER-

OFF DELAY

(SEC.)

135 SEC*180 SEC

YEL

RED

PL2

BLK

PL4

225 SEC

BLK

WHT

BLK

9

87

3

2

1

BLK

RED

BRN

OFF
ON

OFF
ON

ALS2

FRS2

FRS1

N/A

3

2

12

MGVR-2

HUM

DSS

ALS1

(WHEN USED)

NOTE 9

9

6

PL1

4

5

24

W2

VAC

PL4

BHI / LOR

SLAVE

R

TJ

TWIN

TEST

TWINNING

JUMPER

SCHEMATIC DIAGRAM

BLK

WHT

BLWM

WHT

BLK

NOTE 15

PL5

PL5

L2

PR2

L1

PR1

GRY

BRN

YEL

BLU

FACTORY

SETTINGS

*

BLU

RED

TRAN

54321

PL8

YEL

N

R

G

IND

WHT

EAC-1

EAC-2

COMMON

HEAT

LO-GAS

HEAT

HI-GAS

HI-COOL

NOTE 17

PL1

GRN

BLU

16

1

RED

RED

TWIN

ORN

WHT

WHT

BLOWER-OFF DELAY

BLOWER-OFF DELAY

LOW-HEAT ONLY

HIGH-HEAT ONLY

OFF
ON

123 4

GRN

LPS

(WHEN USED)

5

1

Y2

Y

BHT / CLR

MASTER

W/W1

16

NOTE

16

8

9

1

PL9

FU1

SPARE

SPARE

SEC2

SEC1

12

11 10

3

2

TJ

S

M

LED

TEST

W/W1 Y/Y2 R G HUM

24V

W2 Com

LGPS

2

BLWR

NOTE 9

G

RED

BLU

4

6

SW1

K

L

B

U

L

EL

Y

ED

R

O

I

V

N

R

G

N

R

O

2-STAGE

FURNACE

CONTROL

HI

HPS

P

M

1

MGVR-1

W2

N

R

G

B

EL

Y

N

R

B

K

L

B

T

H

W

K

L

B

FSE

GV

C

NOTE 8

N/A

7

10

CPU

Y/Y2

8

G

DEHUM

PL9

BK/PWM 10

BLWM-CTL

NOTES:

DEHUM

N/A
11

3

C1

16

+

OUT

1. Use only copper wire between the disconnect switch and the furnace.

SW2
SW3
SW4

OM

C

8

-

OUT

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

3. Inducer (IDM) motor contains internal auto-reset thermal overload switch.

PL3 3-CIRCUIT IDM CONNECTOR

PL4 6-CIRCUIT CONNECTOR

PL5 1-CIRCUIT CONNECTOR (NOTE 16)

PL7

13

12

10

2

9

8

6

14

R12

C1 1

EM/W2 13

Instructions for details on optimum airflow selections.

electronic control circuits. Restart is attempted every 15 seconds for 2 minutes,

4. Blower motor airflow selections are for nominal conditions. See Installation

5. Blower motor (BLWM) is locked-rotor overload protected by redundant

5

11

C2 3

after which it locks OFF. Reset by turning OFF all control and/or power inputs.

G15

ADJ 7

W/W1 2

downflow models.

6. Replace only with a 3-AMP fuse.

7. Auxiliary limit switches (ALS1 & 2) used on some horizontal and some

8. This wire must be connected to furnace sheet metal for control to prove flame.

9. Factory connected when LGPS not used.

10. Symbols are an electrical representation only.

11. BLOWER-ON DELAY: Gas heating 45 seconds, Cooling/Heat Pump 2 sec.

AB CD

HI

MED

MID

M-HI

EFFY

AC

HP

HP

350

400

M-LO

HI

1

O9

HEAT 11

12. Cooling/Heat Pump BLOWER-OFF DELAY is 90 seconds.

13. IGNITION-LOCKOUT will occur after four consecutive unsuccessful

COOL 5

Y/Y2 14

blower motors. Keep twinning jumper in

+

20 cooling airflow size furnaces only.

-

PL5 connectors are joined without IND on other furnace sizes.

MASTER position.

trials-for-ignition. Control will automatically reset after three hours.

16. Twinning is not permitted with ICM2

17. Terminals (HI-COOL, HI-GAS-HEAT, and LO-GAS-HEAT) are not used for

14. Control must be grounded at pin 10 of 12-pin connector.

15. Inductor is used on 060 or

LO

M-HI

DELAY 4

OM" terminal for about two

C

COMPONENT TEST

BLWM. Do not remove electrical insulators.

+

ICM2

To initiate the component test sequence with no thermostat inputs and

with all inducer Post-Purge and Blower-Off Delay periods completed,

short the "TWIN/TEST" terminal to the "

*

SPST (MANUAL)

SPDT(MANUAL CHANGE-OVER). (NOTE 17)

ALSO STATUS CODE RECALL. (NOTE 17)

JUNCTION

TERMINAL

CONTROL TERMINAL

FACTORY POWER WIRING (115VAC)

FACTORY CONTROL WIRING (24VAC)

FIELD POWER WIRING (115VAC)

FIELD CONTROL WIRING (24VAC)

CONDUCTOR ON CONTROL

FIELD WIRING SCREW TERMINAL

FIELD GROUND

EQUIPMENT GROUND

PL6 2-CIRCUIT HSI CONNECTOR

PL7 14-CIRCUIT CONNECTOR

PL8 5-CIRCUIT CONNECTOR

PL9 16-CIRCUIT CONNECTOR

SW1 HIGH-HEAT-ONLY SWITCH, SPST (MANUAL)*SW2 LOW-HAT-ONLY SWITCH, SPST (MANUAL)*SW3 & 4 BLOWER-OFF DELAY SETTING SWITCHES,

TJ TWINNING JUMPER,

TRAN TRANSFORMER-115VAC/24VAC

TWIN/TEST 1-CIRCUIT TWINNING BUSS CONNECTOR,

L2

BLWM-PWR

54321

PL8

PL5

SEE BLWM-CTL

IND

PL5

NOTE 15

NOTE 17

HI-COOL

LO-GAS-HEAT

COMMON

SPARE

HI-GAS-HEAT

BHT / CLR

C

DSS

FRS1

EAC-2

HSIR EAC-1

BLWR

L1

GRN

NOTE #1

FUSED DISCONNECT

M

SWITCH (WHEN REQ’D)

JB

BLU

GRN

ILK

GRN

IDM

HSI

FSE

(WHEN USED)

NOTE 9

ALS2

ORN

SWITCH

(WHEN USED)

HEAT

SET-UP

SWITCH

BHI / LOR

TO 115VAC FIELD DISCONNECT SWITCH

NOTE 1

ILK

GROUND

EQUIPMENT

GV

HI

P

BRN

HPS

BRN

GRY

LGPS

YEL

NOTE 9

LPS

ORN

RED

FRS2

RED

RED

LS

Y1

U

BL

N

O

R

O

VIO

Connect VIO wire to pin

A, B, C, or D as

designated on furnace

CONNECTION DIAGRAM

rating plate as "PIN".

1

D

C

AB

14

POWER

YEL

YEL
BLU

BLK
WHT

BLK

BLK
BLK

GRN

BLU

RED

RED

PL7

GRN

HI

RED

MID

HP

AC

BLU

400

HI

M-HI

YEL

FAN

-

GRN

LO

MED

CFM

CONTINUOUS

GAS

RISE

HEAT

TEMP

M-HI

HI

NOTE 4

HP

AC

CMFT

EFFY

HP

BLU REDORN

315

PER

TON

CFM

350

COOL

COOL

SIZE

LO

M-LO

ORN

YEL

AFS

LEGEND

=

PWR

-

CONTROL

=

CTL

­+

AFS AIRFLOW SELECTOR

ALS1 AUXILIARY LIMIT SWITCH, OVERTEMP. MANUAL RESET, SPST (N.C.)

ALS2 AUXILIARY LIMIT SWITCH, OVERTEMP. AUTO RESET, SPST (N.C.)

BHI / LOR BLOWER MOTOR SPEED CHANGE RELAY, SPDT

BHT / CLR BLOWER MOTOR SPEED CHANGE RELAY, SPDT

BLWM BLOWER MOTOR, ICM2

BLWR BLOWER MOTOR RELAY, SPST (N.O.)

CPU MICROPROCESSOR AND CIRCUITRY

DSS DRAFT SAFEGUARD SWITCH (N.C.)

EAC-1 ELECTRONIC AIR CLEANER CONNECTION (115 VAC, 1 AMP MAX.)

EAC-2 ELECTRONIC AIR CLEANER CONNECTION (COMMON)

FRS1 FLAME ROLLOUT SWITCH OVERTEMP. MANUAL RESET, SPST (N.C.)

FRS2 FLAME ROLLOUT SWITCH OVERTEMP. MANUAL RESET, SPST (N.C.)

FSE FLAME-PROVING SENSOR ELECTRODE

FU1 FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE, FACTORY INSTALLED

FU2 FUSE, FIELD INSTALLED

GV GAS VALVE, REDUNDANT LOW-HEAT OPERATORS, 2-STAGE

HPS HIGH-HEAT PRESSURE SWITCH, SPST (N.O.)

HPSR HIGH-HEAT PRESSURE SWITCH RELAY, SPST (N.C.)

HSI HOT-SURFACE IGNITER (115 VAC)

HSIR HOT-SURFACE IGNITOR RELAY, SPST (N.O.)

HUM 24VAC HUMIDIFIER CONNECTION (0.5 AMP. MAX.)

IDM INDUCED DRAFT MOTOR, 2-SPEED, SHADED-POLE

IDR INDUCER MOTOR RELAY, SPST (N.O.)

IHI / LOR INDUCER MO TOR SPEED CHANGE RELAY, SPDT

ILK BLOWER DOOR INTERLOCK SWITCH, SPST (N.O.)

IND INDUCTOR (NOTE 16)

JB JUNCTION BOX

2 = HUMIDIFIER

-

1 = VALVE

-

N / A NOT APPLICABLE

PL1 12- CIRCUIT CONNECTOR

LED LIGHT-EMITTING DIODE FOR STATUS CODES

LGPS LOW GAS-PRESSURE SWITCH, SPST (N.O.)

LPS LOW-HEAT PRESSURE SWITCH, SPST (N.O.)

PL2 9-CIRCUIT CONNECTOR

LS LIMIT SWITCH, OVERTEMPERATURE-AUTO RESET, SPST (N.C.)

MGVR MAIN GAS VALVE RELAY DPST (N.O.)

—7—

WARNING

Service should be performed only by qualified persons.

SERVICE

If status code recall is needed, do not remove power or blower door.

LED CODE STATUS

CONTINUOUS OFF Check for 115V at L1 and L2, and 24V at SEC1 and SEC2.
CONTINUOUS ON Control has 24V power.
RAPID FLASHING Line voltage polarity reversed. If twinned, 24V power

to one furnace may be out of phase with power to other furnace.

EACH OF THE FOLLOWING STATUS CODES IS A TWO-DIGIT NUMBER WITH
THE FIRST DIGIT DETERMINED BY THE NUMBER OF SHORT FLASHES AND
THE SECOND DIGIT BY THE NUMBER OF LONG FLASHES.

11 NO PREVIOUS CODE - Stored status codes are erased when power (115V or

24V) to control is interrupted or 48 hours after each fault is cleared.

12 BLOWER ON AFTER POWER UP - Blower runs for 90 seconds, if unit is

powered up during a call for heat (R-W/W1 closed). Note: 2-sec. ON-delay.

13 LIMIT OR FLAME ROLL-OUT (FRS) SWITCH LOCKOUT - Auto-reset after

three hours. FRS switch requires manual-reset.
Check for: - Refer to #33

14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING LOCKOUT - Control will NOT auto-reset.

Check for: - Mis-wired gas valve - Defective control (valve relay)

22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is

de-energized. Inducer will run until fault is cleared.
Check for: - Leaky gas valve - Stuck-open gas valve

23 LOW- OR HIGH-HEAT PRESSURE SWITCH DID NOT OPEN

Check for: - Obstructed pressure tubing

- Defective pressure switch (stuck closed)

24 SECONDARY VOLTAGE FUSE IS OPEN

Check for: - Short-circuit in secondary voltage (24V) wiring

31 HIGH-HEAT PRESSURE SWITCH OR RELAY DID NOT CLOSE OR

REOPENED
Check for: -Control relay may be defective - Refer to #32

32 LOW-HEAT PRESSURE, DRAFT SAFEGUARD , OR AUX-LIMIT

(DOWNFLOW ONLY*) SWITCH DID NOT CLOSE OR REOPENED

Check for: - Proper vent sizing (and condensate pitch with side-wall vent)

- Low inducer voltage (115v) * Blower motor and capacitor

- Defective inducer motor - Defective pressure switch

- Excessive wind - Restricted vent

- Inadequate combustion air supply

- Disconnected or obstructed pressure tubing

33 LIMIT OR FLAME ROLL-OUT (FRS) SWITCH IS OPEN - FRS switch

requires manual-reset.
Check for: - Inadequate combustion air supply (FRS switch only)

- Dirty filter or restricted duct system - Loose blower wheel

- Defective switch or connections

- Blower motor or capacitor failure

34 IGNITION-PROVING FAULT - Control will retry three times before lockout #14.

Check for: - Oxide buildup on flame-proving sensor (clean with fine sandpaper).

- Proper flame-proving microamps (0.5 minimum)

- Proper control ground continuity

- Flame-proving sensor must be ungrounded

- Smooth flame carryover and ignition - Manual valve(s) OFF

43 LOW-HEAT PRESSURE, DRAFT SAFEGUARD, OR AUXILIARY LIMIT

SWITCH OPEN WHILE HIGH-HEAT PRESSURE SWITCH IS CLOSED

Check for: - Disconnected or obstructed pressure tubing

- Defective pressure switch (stuck open)

- Refer to #32 and #33

45 REPLACE CONTROL

Fig. 10—Service Label

320893-101 REV. A

A94169

—8—

NOTES:

Refer to information label on blower compartment door

1.
for procedure for use of LED status codes and problem



solving suggestions.



LED indicator is viewed through window in blower

2.
compartment door.



If 115-vac power is de-energized or interrupted during

3.
a call for heat, the indoor blower will run for 90 sec



before a gas heating cycle begins – Code 12.



After replacing any component, verify correct operating

4.
sequence.

START

Turn thermostat OFF.

On furnace control, note current
settings for setup switches 1 (SW-1)
and 2 (SW-2) then set SW-1 to OFF

and SW-2 to ON.

Cycle 115-v power

off for 3 sec, then on.

Continuous LED?

Yes

Set thermostat to call for heat.

Set FAN to AUTO.

Draft inducer motor starts.

Yes

Is Code 22 displayed?

Yes

Flame present when not normal.

Replace gas valve.

15-sec inducer pre-purge.

Yes

Ignitor warms up and glows

orange/yellow; 17-sec warm-up.

Yes

Main burners ignite.

Yes

Main burners stay on.

Yes

Indoor blower motor starts on

heating speed after 45-sec

warm-up period.

Yes

Furnace runs until call for

heat ends.

Yes

Turn thermostat to OFF; gas valve

shuts off burners; 5-sec inducer 

post purge.

Yes

Indoor blower motor stops after

90, 135, 180, or 225 sec.

Yes

Heating sequence of operation

complete. Remove blower door,

move setup switch 1 (SW-1) to ON

position and repeat process to check

high-stage gas heat operation.

(When finished return SW-1

SW-2 to original desired settings.)

No

No

No

No

No

No

No

No

No

No

and

TROUBLESHOOTING

GUIDE

If LED is flashing rapidly, check line voltage polarity.
If Code 24 is displayed, check for blown fuse.
If LED is OFF, check line voltage and 24-v transformer.
If Code 45 is displayed, replace control.

Is indoor blower on ?

No

24v should be present across C and W. If not, check for:

1. Open thermostat.

2. Open 24-v fuse (FU1) – Code 24.

3. Failed transformer.
If Code 23 is displayed, the pressure switch(es) is stuck closed.

Replace switch and/or check pressure tube for blockage.
System malfunction – Code 21.

115v should be present at the inducer motor. If so, replace inducer
motor. If not, check 115-v wiring.

If Code 32 is displayed check for:

1. Open gas inlet pressure switch (when used).

2. Open pressure switch (LPS) and/or tube – Code 32.

3. Open draft safeguard switch (DSS) – Code 32.

4. Open auxiliary switch (ALS)(downflow only) – Code 32.

5. Check all low-voltage wiring connections.
115v should be present at the ignitor. If so, replace the ignitor; if not,

check 115-vac wiring to ignitor.
LPS, DSS, or ALS open while HPS is closed (high-gas-heat only) –

Code 43.

Control will attempt to light burners 4 times (approximately 1 minute
between attempts – Code 34). Voltage is present at the gas valve for 7
sec during each ignition trial. System will lockout after 4 attempts.

Is the gas valve control knob in the OPEN or ON position?
24v should be present across the gas valve terminals C and M/P

(and C and HI for high-stage test) during the 7 sec ignition trial. If
not, check all low-voltage wiring connections to valve.

If 24v are present, and main gas does not flow:

1. Is supply pressure between 4.5- and 13.6-in. wc? If not,
adjust supply pressure.

2. If supply pressure is between 4.5- and 13.6-in. wc, replace
gas valve.

Check ignitor position.
Check burner carryover gap.
Check manifold pressure (1.3- to 1.7-in. wc for low-stage gas

heat; 3.2- to 3.8-in. wc for high-stage gas heat).
Check for proper orifice size.

Is Code 31 (high-gas-heat only), 32, 33, or 34 displayed? Check
code information label to diagnose.

Check polarity of 115-v power at J-box and control – Rapid
flashing LED.

Check ground continuity from J-box to control.
Check flame sensor microamps (4.0 nominal; 0.5 minimum for

control to recognize flame).

See 2-Stage Gas-Fired Induced-Combustion Furnaces
Troubleshooting Guide (PSC and ICM Blower Motors).

If not, check for:

1. Satisfied thermostat.

2. Open inlet gas pressure switch (when used).

3. Open pressure switch (LPS) – Code 32.

4. Open draft safeguard switch (DSS) – Code 32. 

5. Open auxiliary limit (ALS)(downflow only) – Code 32.

6. Open 24-v fuse (FU1) – Code 24.

7. Open limit switch (LS) – Code 13 or 33.

8. Open flame rollout switch (FRS) – Code 13 or 33.

9. Check 115-v line voltage – LED off.
Check for sources of electrical noise interference (electronic air

cleaners, nearby TV, or radio antennas).

If inducer and burners continue to operate, check for 24v at the
gas valve. If 24v are present, verify that the thermostat is open
across R and W. If no voltage is present, turn the gas valve
control knob to the OFF position. Replace gas valve.

24v should be present across R and C. If not, check for:

1. Open limit switch (LS) – Code 13 or 33.

2. Open flame rollout switch (FRS) – Code 13 or 33.
24v should not be present across R and G. If so, turn thermostat

FAN switch to AUTO.



WARNING

!

ELECTRICAL SHOCK HAZARD

ONLY QUALIFIED AND TRAINED
SERVICE PERSONNEL SHOULD

PERFORM THIS PROCEDURE

24v should be present across R

Yes

No

No

No

No

No

No

No

and C. If not, check for:

Open flame rollout switch

1.
(FRS) – Code 33.



Open limit switch (LS) –

2.
Code 33.



Check all low-voltage wiring

3.
connections.

Replace control only if all checks

Replace control only if Code 45 is
displayed, or if all checks are OK.

Replace control only if Code 45 is
displayed, or if all checks are OK.

Replace control if Code 45 is dis-

played, or if all checks are OK.

Clean flame sensor if microamps

are below nominal.

Replace control only if Code 45 is
displayed, or if all checks are OK.

Replace control only if Code 45 is
displayed, or if all checks are OK.

Replace control only if Code 45 is
displayed, or if all checks are OK.

No

are OK.

A96062

—9—

—10—

—11—

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

© 1997 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231

—12—

Printed in U.S.A. sp0450 Catalog No. 5333-301