Bryant 393AAV User Manual

service and

393AAV

maintenance procedures

GAS-FIRED
INDUCED-COMBUSTION FURNACE

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

These procedures are for size 66,000 through 154,000 Btuh input
units.

Index Page

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

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

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

CARE AND MAINTENANCE..................................................2-8

Air Filter Arrangement.............................................................2

Blower Motor and Wheel......................................................2-3

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

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

Electrical Controls and Wiring .............................................5-8

Troubleshooting...................................................................8-11

Service Label ............................................................................9

Troubleshooting Guide......................................................10-11

Series A

Cancels: SP04-52 SP04-58

ama

®

REGISTERED QUALITY SYSTEM

8-99

CANADIAN GAS ASSOCIATION

APPROVED

R

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.

Follow all safety codes. In the United States, follow all safety
codes including the National Fuel Gas Code (NFGC) NFPA
54-1999/ANSI Z223.1-1999 and the Installation Standards, Warm
Air Heating and Air Conditioning Systems (NFPA 90B)
ANSI/NFPA 90B. In Canada, refer to the CAN/CGA-B149.1- and
.2-M95 National Standard of Canada, 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, CAUTION,
and NOTE. 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. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.

A94085

Fig. 1—Model 393AAV Upflow Furnace

WARNING: The ability to properly perform mainte-

nance on this equipment requires certain expertise, me­chanical skills, tools, and equipment. If you do not

.

possess these, do not attempt to perform any maintenance
on this equipment other than those procedures recom­mended in the User’s Manual. FAILURE TO FOLLOW
THIS WARNING COULD RESULT IN POSSIBLE
DAMAGE TO THIS EQUIPMENT, SERIOUS PER­SONAL INJURY, OR DEATH.

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

—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.
Precautions will prevent electrostatic discharges from
personnel and hand tools which are held during the
procedure. These precautions will help to avoid exposing
the control to electrostatic discharge by putting the
furnace, the control, and the person at the same electro­static potential.

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

THE CONTROL OR ANY WIRE CONNECTED TO THE
CONTROL PRIOR TO DISCHARGING YOUR BODY’S
ELECTROSTATIC CHARGE TO GROUND.

2. Firmly touch a clean, unpainted, metal surface of the
furnace chassis which is close to the control. Tools held in
a person’s hand during grounding will be satisfactorily
discharged.

3. After touching the chassis you may proceed to service the
control or connecting wires as long as you do nothing that
recharges your body with static electricity (for example; DO
NOT move or shuffle your feet, DO NOT touch 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 from its container, dis­charge your body’s electrostatic charge to ground to protect
the control from damage. If the control is to be installed in
a furnace, follow items 1 through 5 before bringing the
control or yourself into contact with the furnace. Put all
used AND new controls into containers before touching
ungrounded objects.

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

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

A. Air Filter Arrangement

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

TABLE 1—FILTER SIZE INFORMATION FOR UPFLOW

FURNACES (IN.)

FURNACE

CASING WIDTH

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

17-1/2 (1) 16 X 25 X 1* (1) 16 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 QUANTITY AND SIZE†

Side Return Bottom Return

FILTER

TYPE

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.

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, kero­sene, 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.

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

1. Disconnect electrical power before removing access doors.

2. Remove blower and control access doors.

3. Release filter retainer from clip at front of furnace casing.
(See Fig. 2.) For side return, clips may be used on either or
both sides of the furnace.

4. Slide filter(s) out.

5. Furnaces are equipped with permanent, washable filters.
Clean filters with tap water. Spray water through filter in
opposite direction of airflow.

6. Rinse and let dry. Oiling or coating of filter is NOT
recommended or required.

7. Reinstall filter(s).

8. Replace blower and control access doors.

9. Restore electrical power to furnace.

B. Blower Motor and Wheel

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

—2—

FLUE
COLLAR

MOUNTING

SCREWS

RELIEF

BOX

GAS

VALVE

CONTROL

HUM

C

24V

OM

GRYW

To ensure long life, economy, and high efficiency, clean accumu-

Fig. 2—Model 393AAV Upflow Furnace

BLOCKED
VENT
SAFEGUARD

PRESSURE
SWITCH

FLUE
COLLECTOR
BOX

FILTER
RETAINER

WASHABLE
FILTER

A99284

lated dirt and grease from blower wheel and motor annually.
The inducer and blower motors are pre-lubricated and require no
additional lubrication. These motors can be identified by the
absence of oil ports on each end of the motor.
Clean blower motor and wheel as follows:

1. Turn off electrical supply to furnace.

2. Remove control and blower access doors.

3. Disconnect blower leads from furnace control. Note wire
color and location for reassembly.

All other factory wires can be left connected, but field
thermostat connections may need to be disconnected de­pending on their length and routing.

4. Remove 2 screws securing control and transformer support
to furnace.

5. Hang control and transformer support to side of furnace
casing.

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

7. Clean blower wheel and motor using a vacuum with soft
brush attachment. Do not remove or disturb balance weights
(clips) on blower wheel blades. The blower wheel should
not be dropped or bent as balance will be affected.

8. If greasy residue is present on blower wheel, remove wheel
from the blower housing and wash it with an appropriate
degreaser. To remove wheel:
a. Mark blower wheel location on shaft before disassembly

to ensure proper reassembly.

b. Loosen setscrew holding blower wheel on motor shaft.

NOTE: Mark blower mounting arms, motor, and blower housing
so motor and each arm is positioned at the same location during
reassembly.

c. Mark blower wheel orientation and cutoff plate location

to ensure proper reassembly.

d. Remove screws securing cutoff plate and remove cutoff

plate from housing.

e. Remove bolts holding motor and motor mounts to

blower housing and slide motor and mounts out of
housing. Disconnect capacitor and ground wire attached
to blower housing before removing motor. Motor mount
belly band need not be removed unless motor is to be
replaced.

f. Remove blower wheel from housing.

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

9. Reassemble motor and blower by reversing items 9a
through 9f. Be sure to reattach ground wire.

10. Reinstall blower assembly in furnace.

11. Reinstall control and transformer support assembly in
furnace.

12. Reconnect blower leads to furnace control.
Refer to furnace wiring diagram and connect thermostat

leads if previously disconnected. (See Fig. 7.)

NOTE: Refer to Table 2 for motor speed lead relocation if leads
were not identified before disconnection.

→TABLE 2—SPEED SELECTOR

COLOR SPEED

Black High Cool

Yellow (When

present)

Blue Medium-Low Heat

Red Low Spare

White Common L2/COM

Medium-High Spare

FACTORY-

ATTACHED TO

CAUTION: Heating air speed selection MUST be ad-

justed to provide proper air temperature rise as specified
on the rating plate. Failure to adjust the heating speed
may shorten heat exchanger life.

13. Turn on electrical supply. Manually close blower access
door switch. Use a piece of tape to hold switch closed.
Check for proper rotation and speed changes between
heating and cooling by jumpering R to W and then R to Y
on furnace control thermostat terminals.

WARNING: Blower access door switch opens 115-v
power to furnace control. No component operation can
occur. Caution must be taken when manually closing this
switch for service purposes. Failure to follow this warn­ing could result in electrical shock, personal injury, or
death.

NOTE: If thermostat terminals are jumpered before blower ac­cess door switch is closed, blower will run for 90 sec before
beginning a heating or cooling cycle.

14. If furnace is operating properly, REMOVE TAPE TO
RELEASE BLOWER ACCESS DOOR SWITCH, replace
blower access door.

→

C. Cleaning Heat Exchanger

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

NOTE: If the heat exchangers get a heavy accumulation of soot
and carbon, they should be replaced rather than trying to clean
them thoroughly due to their intricate design. A build-up of soot
and carbon indicates that a problem exists which needs to be
corrected, such as improper adjustment of manifold pressure,
insufficient or poor quality combustion air, incorrect size, or
damaged manifold orifice(s), improper gas, or a restricted heat
exchanger. Action must be taken to correct the problem.

—3—

If it becomes necessary to clean the heat exchanger because of dust
or corrosion, proceed as follows:

1. Turn gas and electrical power to furnace OFF.

2. Remove control access door.

3. Disconnect vent connector from furnace flue collar.

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

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

a. Blocked vent safeguard switch.
b. Inducer motor.
c. Pressure switch.
d. Limit overtemperature switch(es).
e. Gas valve.
f. Hot surface igniter.
g. Flame-sensing electrode.
h. Flame rollout switch(es), if applicable.

6. Remove complete inducer assembly and relief box from
furnace.

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

8. Remove burner assembly and cell inlet plates. IMPOR­TANT: Replace screws in center panel and cells before
cleaning.

NOTE: Be careful when removing burner assembly to avoid
breaking igniter. See Fig. 4 for correct igniter location.

9. 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 (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.) 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. 3.)

(3.) 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.

(4.) 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.

(5.) Repeat foregoing procedures until each cell in

furnace has been cleaned.

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

cell.

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

clean burner assembly.

(8.) Reinstall cell inlet plates and burner assembly. Care

must be exercised to center burners in cell openings.

10. Clean flame sensor with fine steelwool.

11. Remove old sealant from center panel and collector box
flange and apply new sealant to collector box flange and
reinstall on center panel, making sure all 8 screws are
secure.

NOTE: A releasing agent such as PAM cooking spray or equiva­lent (must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) and RTV sealant
(G.E. 162, 6702, or Dow-Corning 738) are needed before starting
installation. DO NOT substitute any other type of RTV sealant.
G.E. 162 (P771-9003) is available through RCD in 3-oz. tubes.

12. Reinstall relief box and inducer assembly.

NOTE: If inducer assembly gasket is damaged, use RTV sealant
to seal inducer assembly to collector box.

NOTE: A releasing agent such as PAM cooking spray or equiva­lent (must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) and RTV sealant
(G.E. 162, 6702, or Dow-Corning 738) are needed before starting
installation. DO NOT substitute any other type of RTV sealant.
G.E. 162 (P771-9003) is available through RCD in 3-oz. tubes.

13. Reconnect wires to the following components.
a. Blocked vent safeguard switch.

A91252

Fig. 3—Cleaning Heat Exchanger Cell

b. Inducer motor.
c. Pressure switch.
d. Limit overtemperature switch(es).
e. Gas valve.
f. Hot surface igniter.
g. Flame-sensing electrode.
h. Flame rollout switch(es), if applicable.

14. Reinstall vent connector on furnace flue collar. After fully
assembling vent connector to furnace flue collar, securely
fasten vent connector to flue collar with 2 field-supplied,
corrosion-resistant, sheet metal screws located 180° apart
and midway up the collar.

15. Turn electrical power and gas to ON.

16. Set thermostat and check furnace for proper operation.

17. Verify blower airflow and speed changes between heating
and cooling.

18. Check for gas leaks.

—4—

BURNER

13

32"

11

CELL
PANEL

HOT
SURFACE
IGNITER
ASSEMBLY

C

L

7

8"

C

L

IGNITER
ASSEMBLY

"

32

IGNITER

BURNER

Fig. 4—Position of Igniter to Burner

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.

19. Replace control access door.

D. Electrical Controls and Wiring

CAUTION: There may be more than 1 electrical supply

to the unit. Check accessories and cooling unit for
additional electrical supplies.

The electrical ground and polarity for 115-v wiring must be
properly maintained. Refer to Fig. 5 for field wiring information
and to Fig. 7 for furnace wiring information.

NOTE: If the polarity is not correct, the STATUS LED on the
control will flash rapidly and prevent the furnace from heating.
The control system also requires an earth ground for proper
operation of the control and flame-sensing electrode.

→

The 24-v circuit contains an automotive-type, 3-amp fuse located
on the control. (See Fig. 6.) Any shorts of the 24-v wiring during
installation, service, or maintenance will cause this fuse to blow. If
fuse replacement is required, use ONLY a 3-amp fuse. The control
LED will display status code 24 when fuse needs to be replaced.

With power to the unit disconnected, check all electrical connec­tions for tightness. Tighten all screws on electrical connections. If
any smoky or burned connections are found, disassemble the
connection, clean all parts, strip wire, and reassemble properly and
securely.

Reconnect electrical power to the unit and observe unit through 1
complete operating cycle. Electrical controls are difficult to check
without proper instrumentation; if there are any discrepancies in
the operating cycle, contact your dealer and request service.

→

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 short flashes, the second is the number of longs flashes.)

For an explanation of status codes, refer to service label located on
blower access door or Fig. 8, and the troubleshooting guide.

The control stores 1 status code (the last status code to occur) for
a period of 48 hr or until the 115- or 24-v power is interrupted.

A99286

NOTE: Look into blower access door sight glass for current LED
status BEFORE removing the blower access door. Removing
blower access door will open blower access door switch and
terminate 115-v power to control, and status code will be erased.

1. To retrieve status code, proceed with the following:

NOTE: NO thermostat signal shall be present at control, and all
blower off delays must be completed.

a. Leave 115-v power to furnace turned on.
b. Look into blower access door sight glass for current

LED status.

NOTE: Leave blower access panel installed to maintain power to
control to view current LED status.

c. Remove control access door.
d. BRIEFLY remove either wire from the main limit switch

until LED goes out, then reconnect it.

NOTE: If wire to main limit is disconnected longer than 4 sec,
main blower starts, and retrieval request is ignored.

2. When above items have been completed, the following will
occur:

a. LED flashes a status code 4 times. Record this status

code for further troubleshooting.

b. Inducer motor starts and continues to run the entire

component test.

c. Hot surface igniter is energized for 15 sec, then de-

energized.

d. Main blower operates at heating speed for 10 sec, then

turns off.

e. Main blower operates at cooling speed for 10 sec, then

turns off.

f. Inducer motor stops.
Items a through e above will assist in furnace troubleshoot-

ing since all components are functionally operated except
the gas valve. This procedure is also referred to as "Com­ponent Test."

3. Operate furnace through 1 heat cycle to test for proper
operation and check LED status.

4. If furnace is operating properly and LED indicates proper
operation, replace control access door.

5. Component Test can also be initiated by performing the
following:

a. Remove control access door.
b. Remove blower access door.
c. Manually close blower access door switch.

WARNING: Blower access door switch opens 115-v
power to control. No component operation can occur.
Caution must be taken when manually closing this switch
for service purposes. Failure to follow this warning could
result in personal injury or death.

→

d. BRIEFLY short (jumper) TEST, 3/16-in. quick-connect

terminal on control (adjacent to LED status light), and
C

OM-24V terminal on furnace control thermostat termi-

nal block. (See Fig. 6.)

NOTE: If TEST to C

OM-24V terminals are jumpered longer than

2 sec, LED will flash rapidly, and test request will be ignored.

e. Component Test will function as described in item 2

above.

f. Check LED status.

—5—

FIVE WIRE

THREE-WIRE

HEATING-ONLY

BLOWER DOOR SWITCH

BLK

WHT

115-V FIELD-

SUPPLIED

BLK

WHT

GND

AUXILIARY
J-BOX

DISCONNECT

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

NOTE 2

C
O

WCR GY

W
R

THERMOSTAT
TERMINALS

N

GND

FURNACE

T

G

R
O

C

L

Y

24-V

TERMINAL

BLOCK

NOTE 1

CONDENSING
UNIT

TWO
WIRE

NOTES: Connect Y-terminal in furnace as shown for proper blower operation.

1.

2.

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

3.

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

Fig. 5—Heating and Cooling Application Wiring Diagram

FIELD-SUPPLIED
DISCONNECT

208/230- OR
460-V 
THREE
PHASE

208/230-V
SINGLE
PHASE

GND

A98521

115-VAC (L1)

POWER
SUPPLY

HOT SURFACE

CONNECTOR

TEST/TWIN

SEC-1

3-AMP FUSE

COOL

HEAT

IGNITER

BLOWER OFF DELAY
ADJUSTMENT SWITCH

G
R
Y
W

C

OM

24V
HUM

24V THERMOST AT
TERMINALS

HUMIDIFIER TERMINAL
(24-VAC 0.5 AMP MAX)

LED OPERATION &
STATUS LIGHT

HARNESS CONNECTOR

24V TRANSFORMER SEC-2
SPARE 1
BLOWER SPEED

SELECTION TERMINALS
SPARE 2

EAC 1 (BLACK)
EAC-ELECTRONIC AIR CLEANER

TERMINALS (115-VAC 1.0 AMP MAX)
EAC 2 (WHITE)

115-VAC (L2) NEUTRAL
CONNECTION

INDUCER MOTOR
CONNECTOR

Fig. 6—Furnace Control

A99258

—6—

L2

CAP

BLWM

START

OL

LO

SCHEMATIC DIAGRAM

(NATURAL GAS & PROPANE)

HI

MED LO

MED HI

COM

IDM

HSI

2

1

NOT USED

PL3

2

1

3

FRS1 FRS2

FL

PRS

NOTE #13

LS

(WHEN USED)

LGPS

(WHEN USED)

NOTE #11

(WHEN USED)

7

PL1

NOTE #13

1

4

ALS

NOTE #5

NOTE #11

(WHEN USED)

GV

BVSS

NOTE #14

DSS

NOTE #14

3-P

2

3

FSE

2-C

322869-101 REV. E

A98200e

1-M

NOT USED

8

NOT USED

9

6

5

TO 115VAC FIELD DISCONN ECT

(WHEN USED)

(WHEN USED)

SW2

NOTE # 4

NEUTRAL

L1

(WHEN USED)

NOTE #11

NOTE #14

GRY

BLOWER

EQUIPMENT GROUND

LGPS

PRS

ALS

BVSS

DSS

OFF

NOTE #9

PCB

NOTE #7

1

COM

COOL

HEAT

SPARE-1

SPARE-2

HI/LO

BLWR

ILK

ORN

ORN

ORN

ORN

ORN

W

SW1

DELAY

L1

YEL

NOTE #13

NOTE #14

OM

LED

C

HUM

TEST/TWIN

90 SEC

SELECTION CHART

BLOWER OFF DELAY

(NOT ON ALL MODELS)

LS

BLU

135 SEC

RED

180 SEC

EAC-2

EAC-1

HSIR

GV

3-P

1-M

FL

(WHEN USED)NOTE #11

FSE

WHT

4

5

987

6

321

PL1

225 SEC

PR2

PL52

PL2

115VAC

TRAN

PR1

IDR

NOTE #5

2-C

GRN

WHT

BLK

FRS2

FRS1

RED

TRAN

RED

BLU

SEC-2

24 VAC-3A

SEC-1

HI/LO

RELAY

GVR

SEC-2

24VAC

SEC-1

GVR-2

NOTE #6

FU1

R

HUM

TEST/TWIN

NOTE #12

GRN

WHT (COM)

CAP

BRN

OL

BLK (HI)

SPARE-1

FUSE

COOL

FU1

SPEED

SELECT

BLOWER

HSIR IDR BLWR

BRN

BLWM

START

RED (LO)

NOTE #7

BLU (MED LO)

YEL (MED HI)

1.5 AMP

SPARE-2

EAC-1

EAC-2

HEAT

OM

L2

C

PR2
123

PL3

2

1

PL2

PR1

VAC

L1

120

GVR

HI/LO

BLWR

IDR

HSIR

W

NOTE #4

FUSED DISCONNECT

SWITCH (WHEN REQ'D)

JB

BLK

ILK

WHT

WHT (COM)

WHT

WHT

PL5

WHT

12

BLK
BLK

BLK

GVR-1

CPU

G

PCB PRINTED CIRCUIT BOARD

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

BLWM BLOWER MOTOR

PL1 9-CIRCUIT CONNECTOR

OM

C

PL2 2-CIRCUIT PCB CONNECTOR

PL3 3-CIRCUIT IDM CONNECTOR

PL5 2-CIRCUIT HSI/PCB CONNECTOR

PRS PRESSURE SWITCH, SPST-(N.O.)

BVSS BLOCKED VENT SHUTOFF SWITCH, SPST - (N.C.)

CAP CAPACITO R

CPU MICROPROCESSOR AND CIRCUITRY

DSS DRAFT SAFEGUARD SWITCH

EAC-1 ELECTRONIC AIR CLEANER CO N NE C T ION (115 VAC 1.5 AMP M AX.)

NOTES:

EAC-2 ELECTRONIC AIR CLEANER CONNECTION (COMMON)

optimum speed selection.

1. If any of the original equipment wire is replaced use wire rated for 105˚C.

2. Inducer (IDM) and blower (BLW M) motors contain internal auto-reset thermal overload sw itches (OL).

3. Blow er motor speed selections are for average conditions, see installation instructions for details on

4. Use only copper wire between the disconnect switch and the furnace junction box (JB).

5. This wire must be connected to furnace sheetmetal for control to detect flame.

JUNCTION

UNMARKED TERMINAL

PCB TERMINAL

TEST/TWIN COMPONENT TEST & TWIN TERMINAL

TRAN TRANSFORMER-115VAC/24VAC

(FIELD INSTALLED & SUPPLIED)

FL FUSIBLE LINK

FRS FLAME ROLLOUT SW. -MANUAL RESET, SPST-(N.C.)

FSE FLAME PROVING ELECTRODE

FU1 FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE, FACTORY INSTALLE D

FU2 FUSE OR CIRCUIT BREAKER CURRENT INTERRUPT DEVICE

(135 seconds only on some models)

after three hours.

models only.

6. Replace only with a 3 amp fuse.

7. Yellow lead not on all motors.

8. Blow er-on delay, gas heating 45 seconds, cooling or hea t pump 2 seconds.

9. Blow er-off delay, gas heating 90, 135, 180 or 225 seconds, cooling or heat pump 90 seconds.

10. Ignition-lockout will occur after four consecutive unsuccessful trials-for-ignition. C ontrol will auto-reset

11. When used, auxiliary limit switch (A LS) is on some downflow models only. When used, FL is on upflow

FACTORY WIRING (115VAC)

FACTORY WIRING (24VAC)

FIELD WIRING (115VAC)

FIELD WIRING (24VAC)

CONDUCTOR ON PCB

FIELD WIRING TERMINAL

GV GAS VALVE-REDUNDANT OPERATOR S

GVR GAS VALVE RELAY, DPST-(N.O.)

HI/LO BLOWER MOTOR SPEED CHANGE RELAY, SPDT

HSI HOT SURFACE IGN ITOR (115 VA C)

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

HUM 24VAC HUMIDIFIER CONNECTION (.5 AMP. MAX.)

IDM INDUCED DRAFT MOTOR

IDR INDUCE D DRAFT RELAY, SPST-(N.O.)

ILK BLOWER ACCESS PANEL INTERLOCK SW ITCH, SPST-(N.O.)

installed.

12. Some models may have spade quick connect terminals.

13. Factory connected when LGPS is not used.

14. Factory connected when BVSS is not used. BVSS used when Chimney Adapter Accessory Kit is

FIELD GROUND

EQUIPMENT GROUND

FIELD SPLICE

PLUG RECEPTACLE

Fig. 7—Unit Wiring Diagram

JB JUNCTION BOX

LED LIGHT-EMITTING DIODE FOR STATUS CODES

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

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

OL AUTO-RESET INTERNAL MOTOR OVERLOAD TEMP. SW.

Y

L1

NEUTRAL

FU2

GRN

WHT

BLK

GRN

IDM

BLK

HSI

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

LEGEND

—7—

g. If LED status indicates proper operation, RELEASE

BLOWER ACCESS DOOR SWITCH, replace blower
access door, and replace control access door.

E. Troubleshooting

Refer to the service label. (See Fig. 8.) Pages 9 and 10 contain 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.

—8—

SERVICE

If status code recall is needed, do not remove power or b lower door. Briefly remove and then
reconnect one main limit wire to display stored status code.

LED CODE

CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and
CONTINUOUS ON - Control has 24VAC power.

RAPID FLASHING - Line voltage (115VAC) polarity reversed. If twinned, refer

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.

NO PREVIOUS CODE - Stored status codes are erased when power

11

(115VAC or 24VAC) to control is interrupted or 48 hours after each fault is cleared.

BLOWER ON AFTER POWER UP (115VAC or 24 VA C) - Blower runs for 90

12

seconds, if unit is powered up during a call for heat (R-W closed).

LIMIT OR FLAME ROLL-OUT SWITCH LOCKOUT - Control will auto reset after

13

three hours. Reset switch or replace fuse link. Ref er to #33.

IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.

14

GAS HEA TING LOCKOUT - Control will NOT auto reset.

21

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

ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas v alve is

22

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

PRESSURE SWITCH DID NOT OPEN - Check for:

23

- Obstructed pressure tubing. - Pressure switch stuck closed.

SECONDAR Y VOL TAGE FUSE IS OPEN

24

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

PRESSURE, DRAFT SAFEGU ARD, AUX-LIMIT SWITCH (when used*) OR BLOCKED

31

VENT SWITCH (when used) DID NO T CLOSE OR REOPENED
(DOWNFLOW ONLY*) If open longer than five minutes , inducer shuts off for 15

minutes before retry. Chec k for: - Proper vent sizing

- Low inducer voltage (115VAC) - Defective inducer motor

- Defective Blower motor or capacitor - Restricted vent

*

- Defective pressure s witch - Excessive wind

- Inadequate combustion air supply

- Disconnected or obstructed pressure tubing
If it opens after trial for ignition period, blower will come on f or 90 second
recycle delay.

LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN - If open longer than three

33

minutes, code changes to #13. Flame roll-out switch requires manual reset.
Check for: - Defective blower motor or capacitor.

- Dirty filter or restricted duct system.

- Loose blower wheel.

- Defective s witch or connections.

- Inadequate combustion air supply (Flame Roll-out Switch or fuse link open).

- Open Flame Roll-out Switch, or fuse link. Manual reset or replace .

IGNITION PROVING FAILURE - Control will try three more times before

34

lockout #14 occurs. If flame signal lost after trial for ignition period, blower
will come on for 90 second recycle delay. Check for:

- Oxide buildup on flame sensor (clean with fine steel wool).

- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal).

- Gas valve defective or gas valve turned off.

- Defective Hot Surf ace Ignitor - Manual valve shut-off.

- Low inlet gas pressure. - Control ground continuity

- Green wire MUST be connected to furnace sheet metal.

- Inadequate flame carryover or rough ignition.

- Flame sensor must be ungrounded.

SEC-2.

to twinning kit instructions.

COMPONENT TEST

To initiate the component test sequence, shut OFF the room thermostat or
disconnect the "R" thermostat lead. Briefly short the TEST terminal to the "Com
24V" terminal. Status LED will flash code and then turn ON the inducer motor.
The inducer motor will run for the entire component test. The hot surface ignitor,
blower motor-heat speed, and blower motor-cool speed will be turned ON for
10-15 seconds each. Gas Valve and Humidifier will not be turned on.

6

32

9

8

7

5

4

1

LED

TEST

HUM

STATUS

Com

W

24V

Y

320615-102 REV. K (LIT)

G

R

Fig. 8—Service Label

—9—

A99233

NO

Close circuit breaker and

go back to start.

TROUBLESHOOTING GUIDE

YES

Close door switch and go to start.Is red LED status light on? Is door switch closed?

NO

Is circuit breaker closed?

NO

YES

Is there 115v going to switch?

NO

NO

YES

YES

Is 24 vac present at W, Y, or G

terminals on the control?

Replace control if it does not

respond to 24-vac signal at W, Y,

or G screw terminals.

Check for continuity in wire from circuit

breaker to furnace.

NO

Check room thermostat or

interconnecting cable.

NO

YES

Replace door switch.Replace control center.

Replace transformer.

Does control respond to W, Y,

or G 24-vac thermostat signals?

Run system through a heating or

cooling cycle to check operation.

Status codes are erased after 48

hrs or whenever power (115v

or 24v) is interrupted.

NO

YES

Is there 115v at L1 and L2?

NO

YES

START

YES

Check for correct line voltage

polarity. If units are twinned,

Is there 24v at SEC-1 and SEC-2?

check for proper low-voltage

YES

Is red LED status light blinking

rapidly without a pause?

(24v) transformer phasing.

Check for previous fault by

momentarily shorting the TEST

terminal and the C terminal until

the LED goes out. LED will flash

the status code of any previous

NO

NO

Is red LED status light blinking

YES

ON/OFF slowly with a

combination of short and long

flashes?

—10—

fault or the code No. 11 (1 short

and 1 long flash) if no previous

fault. After the control repeats the

code 3 times, the control will go

through a brief component test

sequence. The inducer will start

and run for the entire component

test. The HSI, blower motor heat

speed, and blower motor cool

speed will run for 10-15 sec each.

Determine status code. The

status code is a 2 digit number

with the first digit determined by

the number of short flashes and

the second digit by the number of

long flashes.

YES

Was there a previous fault code

other than No. 11?

Go to section with status code

determined.

A99123

Replace control center.

NO

YES

Unplug ignitor harness from control

center and inititate another

component test sequence. Check

for 115v between pins 1 and 2 on

the control center. Was 115v present

for the 17-sec period?

Check for continuity in the harness

and ignitor. Replace defective

component.

Check connections. If OK, replace

control center.

NO

Reconnect the R thermostat lead

and set thermostat to call for heat.

Connect voltmeter across gas valve

connections. Does gas valve

Check that all gas valves are turned

on. Replace valve.

NO

YES

receive 24v?

YES

Does gas valve open and allow gas

to flow?

NO

rough ignition.

• Low inlet gas pressure.

• Inadequate flame carryover on

Check for:

NO

YES

Do main burners ignite?

Repeat call for heat and check flame

sensor current during trial for ignition

NO

YES

Do main burners stay on?

Allow blower to come on and repeat

test to check for intermittent

Check connections and retry. If

current is near typical value and

control will not stay on, replace

control center.

YES

period. Is the DC microamps

below 0.5?

operation.

Replace electrode.

NO

Clean flame sensor with fine

sandpaper and recheck current.

Current is nominally 4.0 to 6.0 microamps.

Is current near typical value?

Replace control center.

NO

YES

YES

Will main burner ignite and stay on?

Fixed.

NOT CLOSE OR REOPEN - If

open longer than 5 minutes,

31 PRESSURE SWITCH WILL

are erased after 48 hrs or

11 NO PREVIOUS FAULT - Faults

sag.

inducer shuts off for 15 minutes

before retry.

Check for:

• Proper vent sizing or pitch or

whenever power (115v or 24v) is

interrupted. Run system through

a heating or cooling cycle to

check system.

connections. If it opens after

trial for ignition period, blower

will come on for 90 sec

• Vent restrictions or high winds.

• Defective inducer motor.

• Low line voltage (115v).

• Motor start capacitor.

• Low inlet gas pressure.

• Defective pressure switch or

UP (115V OR 24V) - Normal

operation. Blower will run for 90

sec when furnace power is

12 BLOWER ON AFTER POWER

recycle delay.

interrupted during a call for heat,

R-W closed.

13 LIMIT OR FLAME ROLLOUT

• Inadequate combustion air.

SWITCH IS OPEN - If

limit switch is open longer than 3

minutes, code changes to No. 13.

Check for:

• Blower motor failure.

33 LIMIT OR FLAME ROLLOUT

SWITCH LOCKOUT -

Limit switch was open longer

than 3 minutes. Auto-reset will

occur after 3 hrs. Flame rollout

switch requires manual reset.

See No. 33

14 IGNITION LOCKOUT - System

manual reset.

Inadequate combustion air

supply (flame rollout switch

• Motor start capacitor.

• Open flame rollout switch,

•

failed to ignite gas and prove

flame in 4 attempts. Control will

auto-reset in 3 hrs.

See No. 34

connections.

only).

• Dirty filter.

• Defective limit switch or

Turn off power and wait 5

minutes to retry.

Check for:

21 GAS HEATING LOCKOUT -

—11—

• Loose blower wheel.

If flame is not sensed during the

trial for ignition period, the control

will repeat the ignition sequence

3 more times before going into

lockout, No. 14.

If flame signal is lost after trial for

34 IGNITION PROVING FAILURE -

wire.

on control.

• Miswire or short to gas valve

• Stuck closed gas valve relay

SIGNAL - Flame was sensed

while gas valve was

de-energized. Inducer will run

22 ABNORMAL FLAME PROVING

NO

ignition period, blower will come

on for 90-sec recycle delay.

Check for the following items first

before proceding to the next step.

or leak.

until fault is cleared.

Check for:

• Stuck open gas valve solenoid

to furnace sheet metal.

• Gas valve turned off.

• Manual shut-off valve.

• Green wire must be connected

To determine whether the

problem is in the gas valve,

ignitor, or flame sensor, the

• Defective control center.

pressure tubing.

• Defective pressure switch.

NOT OPEN - Check for:

• Disconnected or obstructed

23 PRESSURE SWITCH WILL

system can be operated in the

component test mode to check

the ignitor. First, remove the

R thermostat connection from the

control center and initiate the

component test sequence. Does

the ignitor glow orange/white hot

by the end of the 17-sec warm-up

period?

including thermostat leads

shorting to ductwork or

furnace cabinet. Disconnect

thermostat leads to isolate

OPEN - Check for:

• Short in low-voltage wiring

24 LOW-VOLTAGE FUSE IS

short circuit.

YES

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

© 1999 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231

—12—

Printed in U.S.A. sp0458 Catalog No. 5339-304