Bryant GAS-FIRED INDUCED-COMBUSTION FURNACE 393AAV Installation and user guide

NOTE: Read the entire instruction manual before starting the
installation.
TABLE OF CONTENTS
SAFETY CONSIDERATIONS.....................................................1
INTRODUCTION..........................................................................2
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS PRO-
CEDURE........................................................................................2
CARE AND MAINTENANCE.....................................................2
Cleaning and/or Replacing Air Filter.......................................2
Blower Motor and Wheel.........................................................3
Cleaning Heat Exchanger.........................................................4
Electrical Controls and Wiring.................................................5
WIRING DIAGRAMS...................................................................9
Troubleshooting..............................................................................9
SAFETY CONSIDERATIONS
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified person-
nel should install, repair, or service heating equipment.
Untrained personnel can perform basic maintenance functions
such as 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 (NFGC) NFPA No.
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 current edition of the
National Standard of Canada CAN/CGA-B149.1- and .2-M95
Natural Gas and Propane Gas 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 these 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 hazards
which could result in personal injury or death. CAUTION is used
to identify unsafe practices which would result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation
WARNING: The ability to properly perform mainte-
nance on this equipment requires certain expertise, me-
chanical skills, tools, and equipment. If you do not
possess these, do not attempt to perform any maintenance
on this equipment other than those procedures recom-
mended in the User’s Manual. FAILURE TO FOLLOW
THIS WARNING COULD RESULT IN POSSIBLE
DAMAGE TO THIS EQUIPMENT, SERIOUS PER-
SONAL INJURY, OR DEATH.
Fig. 1—Model 393AAV Upflow Furnace
A94085
REGISTERED QUALITY SYSTEM
C
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e
r
C
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r
p
o
r
a
t
i
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R
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G
I
S
T
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E
D
F
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9
0
0
1
#
A
2
8
8
3
®
EFFICIENCY
RATING
CERTIFIED
CERTIFIED
Service and
Maintenance Procedures
GAS-FIRED
INDUCED-COMBUSTION FURNACE
Cancels: SP04-58 SP04-61
10-00
393AAV
Series B&C
—1—

CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper and
dangerous operation.
INTRODUCTION
These instructions are written for the Gas-Fired Induced Combus-
tion Furnace.
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 electro-
static 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 un-
grounded objects, etc.).
4. If you touch ungrounded objects (recharge your body with
static electricity), firmly touch furnace again before touch-
ing control or wires.
5. Use this procedure for installed and uninstalled (un-
grounded) furnaces.
6. Before removing a new control from its container, dis-
charge your body’s electrostatic charge to ground to protect
the control from damage. If the control is to be installed in
a furnace, follow items 1. through 5. before bringing the
control or yourself into contact with the furnace. Put all
used AND new controls into containers before touching
ungrounded objects.
7. An ESD service kit (available from commercial sources)
may also be used to prevent ESD damage.
CARE AND MAINTENANCE
For continuing high performance and to minimize possible equip-
ment failure, it is essential that periodic maintenance be performed
on this equipment. Consult your local dealer as to the proper
frequency of maintenance and availability of a maintenance
contract.
WARNING: Never store anything on, near, or in contact
with 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.
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, per-
sonal injury can result from sharp metal edges, etc.;
therefore, be careful when removing parts.
I. CLEANING AND/OR REPLACING AIR FILTER
The air filter arrangement may vary depending on application.
NOTE: If the filter has an airflow direction arrow, the arrow must
point toward the blower.
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.
To clean or replace filters, proceed as follows:
1. Filters installed in media cabinet adjacent to furnace (see
Fig. 2)
a. Turn off electrical supply to furnace
Fig. 2—Model 393AAV Upflow Furnace
A99294
AIR FLOW
—2—

b. Remove filter cabinet door.
c. Slide filter out of cabinet.
d. If equipped with permanent, washable filter, clean filter
by spraying cold tap water through filter in opposite
direction of airflow. Rinse filter and let dry. Oiling or
coating of the filter is not recommended.
e. If equipped with factory-specified disposable media
filter, replace only with media filter having the same part
number and size.
f. Slide filter into cabinet.
g. Replace filter cabinet door.
h. Turn on electrical supply to furnace.
2. Filters installed in side(s) and/or bottom of blower compart-
ment (See Fig. 2)
a. Disconnect electrical power before removing access
doors.
b. Remove blower and control access doors.
c. 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.
d. Slide filter(s) out.
e. Furnaces are equipped with permanent, washable filters.
Clean filters with tap water. Spray water through filter in
opposite direction of airflow.
f. Rinse and let dry. Oiling or coating of filter is NOT
recommended or required.
g. Reinstall filter(s)
h. Replace blower and control access doors
i. Restore electrical power to furnace.
II. BLOWER MOTOR AND WHEEL
The following items should be performed by a qualified service
technician:
To ensure long life, economy, and high efficiency, clean accumu-
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 door.
3. Disconnect blower leads from furnace control. Notice wire
color and location for reassembly.
All other factory wires can be left connected, but field
thermostat connections may need to be disconnected de-
pending 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 a 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
bend 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 (See Fig. 7), and connect
thermostat leads if previously disconnected.
NOTE: Refer to Table 1 for motor speed lead relocation if leads
were not identified before disconnection
CAUTION: Heating air speed selection MUST be ad-
justed to provide proper 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.
TABLE 1—SPEED SELECTOR
COLOR SPEED FACTORY- ATTACHED
TO
Black High Cool
Yellow (When
Present) Medium High Spare
Blue Medium Low Heat
Red Low Spare
White Common L2/COM
—3—

WARNING: Blower access door switch opens 115-v
power to control center. No component operation can
occur. Caution must be taken when manually closing this
switch for service purposes. Failure to follow this warn-
ing could result in electrical shock, personal injury, or
death.
NOTE: If thermostat terminals are jumpered before blower ac-
cess 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.
III. 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.
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 to 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 ignitor.
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 before cleaning.
NOTE: Be very careful when removing burner assembly to avoid
breaking ignitor. See Fig. 3 for correct ignitor 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-Rootertcable).
(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.) 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. 4.)
(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.
Fig. 3—Position of Ignitor to Burner
A93347
BURNER
IGNITOR
11 32"
78"C
L
C
L
IGNITOR
ASSEMBLY
CELL
PANEL
BURNER 13 32"
HOT
SURFACE
IGNITOR
ASSEMBLY
Fig. 4–Cleaning Heat Exchanger Cell
A91252
—4—

(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 steel wool
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 equiva-
lent (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 equiva-
lent (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.
b. Inducer motor.
c. Pressure switch.
d. Limit overtemperature switch(es).
e. Gas valve.
f. Hot surface ignitor.
g. Flame-sensing electrode
h. Flame rollout switch(es), if applicable.
14. Reinstall vent connector to 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 degrees
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.
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.
IV. ELECTRICAL CONTROLS AND WIRING
CAUTION: There may be more than 1 electrical supply
to the unit. Check accessories and cooling the unit for
additional electrical supplies.
The electrical ground and polarity for 115-v wiring must be
maintained properly. 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.
Fig. 5–Heating and Cooling Application Wiring Diagram
A98521
115-V FIELD-
SUPPLIED
DISCONNECT
AUXILIARY
J-BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-ONLY
FIVE WIRE
NOTE 1
NOTE 2 FIELD-SUPPLIED
DISCONNECT
CONDENSING
UNIT
TWO
WIRE
FURNACE
C
O
N
T
R
O
L
R
G
C
WCR GY
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
BLOWER DOOR SWITCH
WHT
BLK
WHT
BLK
NOTES: Connect Y-terminal in furnace as shown for proper blower operation.
Some thermostats require a "C" terminal connection as shown.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
W
Y
GND
THERMOSTAT
TERMINALS
1.
2.
3.
—5—

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 connec-
tions 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 of 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, Fig. 8, or 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.
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 ignitor 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 troubleshooting 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.
Fig. 6—Furnace Control
A99258
G
R
Y
W
3-AMP FUSE
C OM
24V
HUMIDIFIER TERMINAL
(24-VAC 0.5 AMP MAX)
LED OPERATION &
STATUS LIGHT
HARNESS CONNECTOR
24V TRANSFORMER SEC-2
SPARE 1
SPARE 2
EAC 1 (BLACK)
EAC-ELECTRONIC AIR CLEANER
TERMINALS (115-VAC 1.0 AMP MAX)
EAC 2 (WHITE)
115-VAC (L2) NEUTRAL
CONNECTION
24V THERMOSTAT
TERMINALS
BLOWER SPEED
SELECTION TERMINALS
INDUCER MOTOR
CONNECTOR
115-VAC (L1)
POWER
SUPPLY
HOT SURFACE
IGNITER
CONNECTOR
HEAT
COOL
BLOWER OFF DELAY
ADJUSTMENT SWITCH
SEC-1
TEST/TWIN
HUM
—6—

Fig. 7—Unit Wiring Diagram A00304
PCB
BLOWER OFF DELAY
SELECTION CHART
90 SEC
135 SEC
180 SEC
225 SEC
GVR
HI/LO
RELAY
SEC-1 SEC-2
PL1 321
654
987
LED
TEST/TWIN
BLOWER
OFF
DELAY
G
R
Y
W
C
HUM
HSIR IDR BLWR
BLOWER
SPEED
SELECT
FU1
COOL
HEAT
L2
PL3
PL2
VAC
120
L1 PR1 1
2
1
2
3
PR2
24 VAC-3A
FUSE
SPARE-2
SPARE-1
EAC-1
EAC-2
C
1.5 AMP
12
PL5 WHT
BLK
WHT
WHT
BLK
BLK
HSI
BLK
WHT
WHT (COM)
RED (LO)
BLU (MED LO)
NOTE #7
OL
START
BLWM
YEL (MED HI)
BLK (HI)
BRN
BRN
TRAN
BLU
RED
BLK
WHT
WHT (COM)
CAP
RED
RED
ORN
FUSED DISCONNECT
SWITCH (WHEN REQ’D)
NOTE #4
FU2
BLK
WHT
JB
LEGEND
ALS AUXILIARYLIMIT SWITCH, OVERTEMP. -MANUAL RESET, SPST-(N.C.)
BLWR BLOWER MOTOR RELAY, SPST-(N.O.)
BLWM BLOWER MOTOR
BVSS BLOCKED VENT SHUTOFF SWITCH, SPST - (N.C.)
CAP CAPACITOR
CPU MICROPROCESSOR AND CIRCUITRY
DSS DRAFT SAFEGUARD SWITCH
EAC-1 ELECTRONIC AIR CLEANER CONNECTION (115 VAC 1.5 AMP MAX.)
EAC-2 ELECTRONIC AIR CLEANER CONNECTION (COMMON)
FL FUSIBLE LINK
FRS FLAME ROLLOUT SW. -MANUALRESET, SPST-(N.C.)
FSE FLAME PROVING ELECTRODE
FU1 FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE, FACTORY INSTALLED
FU2 FUSE OR CIRCUIT BREAKER CURRENT INTERRUPT DEVICE
(FIELD INSTALLED & SUPPLIED)
GV GAS VALVE-REDUNDANT OPERATORS
GVR GAS VALVE RELAY, DPST-(N.O.)
HI/LO BLOWER MOTOR SPEED CHANGE RELAY, SPDT
HSI HOT SURFACE IGNITOR (115 VAC)
HSIR HOT SURFACE IGNITOR RELAY, SPST-(N.O.)
HUM 24VAC HUMIDIFIER CONNECTION (.5 AMP. MAX.)
IDM INDUCED DRAFT MOTOR
IDR INDUCED DRAFT RELAY, SPST-(N.O.)
ILK BLOWER ACCESS PANEL INTERLOCK SWITCH, SPST-(N.O.)
JB JUNCTION BOX
LED LIGHT-EMITTING DIODE FOR STATUS CODES
LGPS LOW GAS PRESSURE SWITCH, SPST-(N.O.)
LS LIMIT SWITCH, AUTORESET, SPST(N.C.)
OL AUTO-RESET INTERNAL MOTOR OVERLOAD TEMP. SW.
PCB PRINTED CIRCUIT BOARD
PL1 9-CIRCUIT CONNECTOR
PL2 2-CIRCUIT PCB CONNECTOR
PL3 3-CIRCUITIDMCONNECTOR
PL5 2-CIRCUIT HSI/PCB CONNECTOR
PRS PRESSURE SWITCH, SPST-(N.O.)
TEST/TWIN COMPONENT TEST & TWIN TERMINAL
TRAN TRANSFORMER-115VAC/24VAC
JUNCTION
UNMARKED TERMINAL
PCB TERMINAL
FACTORY WIRING (115VAC)
FACTORY WIRING (24VAC)
FIELD WIRING (115VAC)
FIELD WIRING (24VAC)
CONDUCTOR ON PCB
FIELD WIRING TERMINAL
FIELD GROUND
EQUIPMENT GROUND
FIELD SPLICE
PLUG RECEPTACLE
L1 L2
L1 BLWR
HI/LO
TO 115VAC FIELD DISCONNECT
NOTE #4
EQUIPMENT GROUND
SPARE-2
HEAT
SPARE-1
COOL NOTE #7
COM
HSIR EAC-1
START
OL
COM
HI
MED HI
MED LO
LO
BLWM
SCHEMATIC DIAGRAM
(NATURAL GAS & PROPANE)
EAC-2
11HSI
2
PL52
PL2
3PL3
PR2
115VAC
PR1
TRAN 24VAC
1
2
IDR
TEST/TWIN
FU1 NOTE #6
CAP
L2
PL1
8
FSE
9
6
5
CPU
HSIR IDRBLWR
Y
G
C
R
W
GVR-2
SEC-1
HI/LO GVR
SEC-2
NOTES:
322869-101 REV. H
1. If any of the original equipment wire is replaced use wire rated for 105°C.
2. Inducer (IDM) and blower (BLWM) motors contain internal auto-reset thermal overload switches (OL).
3. Blower motor speed selections are for average conditions, see installation instructions for details on
optimum speed selection.
4. Use only copper wire between the disconnect switch and the furnace junction box (JB).
5. This wire must be connected to furnace sheetmetal for control to detect flame.
6. Replace only with a 3 amp fuse.
7. Yellow lead not on all motors.
8. Blower-on delay, gas heating 45 seconds, cooling or heat pump 2 seconds.
9. Blower-off delay, gas heating 90, 135, 180 or 225 seconds, cooling or heat pump 90 seconds.
(135 seconds only on some models)
10. Ignition-lockout will occur after four consecutive unsuccessful trials-for-ignition. Control will auto-reset
after three hours.
11. When used, auxiliary limit switch (ALS) is on some downflow models only. When used, FL is on
upflow models only.
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
installed.
15. Gas valve leads are interchangeable on single stage valves.
BLK
OM
SW2
SW1
OM
3
4
7
1
OM
HUM
IDM
ILK
DSS BVSS
PRS
ILK
L1
NEUTRAL
IDM
(WHEN USED)
NOTE #14
NOT USED
NOT USED
NOT USED
FSE
BLU
PRS
DSS
BVSS
(WHEN USED)
NOTE #14
WHT
LS
FL
(NOT ON ALL MODELS)
NOTE #9
FRS1 FRS2
LS FL
NOTE #12
ORN ORN ORN
ALS
(WHEN USED)
ORN
NOTE #11
LGPS
(WHEN USED)
NOTE #13
NOTE #14
NOTE #11
2
GVR-1
NOTE #14
ALS
(WHEN USED)
(WHEN USED)
NOTE #13 LGPS
(WHEN USED)
NOTE #13
YEL
FRS1 FRS2
(WHEN USED) NOTE #11
GRN/YEL
GRN/YEL
GND
NOTE #5
GRN/YEL NOTE #5
GRN/YEL
NOTE #15
NOTE #15
GV
GV
—7—

Fig. 8—Service Label
A99233
SERVICE
G
R
Y
W
Com
HUM
TEST
LED
LED CODE STATUS
24V
11
12
13
14
21
22
23
24
31
33
34
*
98
65
32 1
4
7
COMPONENTTEST
NO PREVIOUS CODE - Stored status codes are erased when power
(115VAC or 24VAC) to control is interrupted or 48 hours after each fault is cleared.
BLOWER ON AFTER POWER UP (115VAC or 24VAC) - Blower runs for 90
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
three hours.Reset switch or replace fuse link. Refer to #33.
IGNITION LOCKOUT - Control will auto-reset after three hours.Refer to #34.
GAS HEATING LOCKOUT - Control will NOT auto reset.
Check for: - Mis-wired gas valve -Defective control (Valve relay)
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
PRESSURE SWITCH DID NOT OPEN - Check for:
- Obstructed pressure tubing. - Pressure switch stuck closed.
SECONDARYVOLTAGE FUSE IS OPEN
Check for: - Short circuit in secondary voltage (24VAC) wiring.
PRESSURE, DRAFT SAFEGUARD,AUX-LIMIT SWITCH (when used*) OR BLOCKED
VENT SWITCH (when used) DID NOT CLOSE OR REOPENED
(DOWNFLOW ONLY*) If open longer than five minutes, inducer shuts off for 15
minutes before retry. Check for: - Proper vent sizing
- Low inducer voltage (115VAC) - Defective inducer motor
- Defective Blower motor or capacitor - Restricted vent
- Defective pressure switch - Excessive wind
- Inadequate combustion air supply
- Disconnected or obstructed pressure tubing
If it opens after trial for ignition period, blower will come on for 90 second
recycle delay.
LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN - If open longer than three
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 switch 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
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 Surface 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.
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.
If status code recall is needed, do not remove power or blower door.Briefly remove and then
reconnect one main limit wire to display stored status code.
CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and
SEC-2.
CONTINUOUS ON - Control has 24VAC power.
RAPID FLASHING - Line voltage (115VAC) polarity reversed.If twinned, refer
to twinning kit instructions.
EACH OFTHE 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.
320615-102 REV.K (LIT)
—8—

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
COM-24V terminal on furnace control thermostat termi-
nal block. (See Fig. 6.)
NOTE: If TEST to COM-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.
g. If LED status indicates proper operation, RELEASE
BLOWER ACCESS DOOR SWITCH, replace blower
access door, and replace control access door.
WIRING DIAGRAMS
Refer to Fig. 5, 6, and 7 for wiring diagrams.
TROUBLESHOOTING
Refer to service label. (See Fig. 8.) The Troubleshooting 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 you identify the problem or failed component.
After replacing any component, verify correct operation sequence.
—9—

Troubleshooting Guide
A99123a
Is circuit breaker closed?
Close door switch and go to start.Is red LED status light on? Is door switch closed?
Is red LED status light blinking
rapidly without a pause?
Is there 115v going to switch?
Replace door switch.Replace control center.
Replace transformer.
Is red LED status light blinking
ON/OFF slowly with a
combination of short and long
flashes?
Check for correct line voltage
polarity. If units are twinned,
check for proper low-voltage
(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
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.
Was there a previous fault code
other than No. 11? 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.
Go to section with status code
determined.
Is there 115v at L1 and L2?
Close circuit breaker and
go back to start.
Check for continuity in wire from circuit
breaker to furnace.
NO NO NO
NO NO
NO
YES
YES
YES
YES
YES
YES
YES
NO
NO
YES
YES
YES
START
Is there 24v at SEC-1 and SEC-2?
NO 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 room thermostat or
interconnecting cable.
YES
NO
NO
—10—

A99123b
11 NO PREVIOUS FAULT - Faults
are erased after 48 hrs or whenever power (115v or 24v) is interrupted. Run system through a heating or cooling cycle to check system.
12 BLOWER ON AFTER POWER
UP (115V OR 24V) - Normal operation. Blower will run for 90 sec when furnace power is interrupted during a call for heat, R-W closed.
13 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
failed to ignite gas and prove flame in 4 attempts. Control will auto-reset in 3 hrs. See No. 34
21 GAS HEATING LOCKOUT -
Turn off power and wait 5 minutes to retry. Check for:
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?
Replace control center.
Check for continuity in the harness and ignitor. Replace defective component.
Reconnect the R thermostat lead and set thermostat to call for heat. Connect voltmeter across gas valve connections. Does gas valve receive 24v?
Check connections. If OK, replace control center.
Does gas valve open and allow gas to flow? Check that all gas valves are turned
on. Replace valve.
Do main burners ignite? Do main burners stay on? Allow blower to come on and repeat test to check for intermittent operation.
Repeat call for heat and check flame sensor current during trial for ignition period. Is the DC microamps below 0.5?
Check connections and retry. If current is near typical value and control will not stay on, replace control center.
Clean flame sensor with fine sandpaper and recheck current. Current is nominally 4.0 to 6.0 microamps. Is current near typical value? Replace electrode. Will main burner ignite and stay on? Replace control center. Fixed.
• Stuck closed gas valve relay
on control.
• Miswire or short to gas valve
wire.
22 ABNORMAL FLAME PROVING
SIGNAL - Flame was sensed while gas valve was de-energized. Inducer will run until fault is cleared. Check for: • Stuck open gas valve solenoid
or leak.
• Defective control center.
23 PRESSURE SWITCHWILL
NOT OPEN - Check for: • Disconnected or obstructed
pressure tubing.
• Defective pressure switch.
24 LOW-VOLTAGE FUSE IS
OPEN - Check for: • Short in low-voltage wiring
including thermostat leads shorting to ductwork or furnace cabinet. Disconnect thermostat leads to isolate short circuit.
31 PRESSURE SWITCHWILL
NOT CLOSE OR REOPEN - If open longer than 5 minutes, inducer shuts off for 15 minutes before retry. Check for:
• Proper vent sizing or pitch or
sag.
• Vent restrictions or high winds. • Defective inducer motor. • Low line voltage (115v). • Motor start capacitor. • Low inlet gas pressure. • Defective pressure switch or
connections. If it opens after trial for ignition period, blower will come on for 90 sec recycle delay.
• Inadequate combustion air.
33 LIMIT OR FLAME ROLLOUT
SWITCH IS OPEN - If limit switch is open longer than 3 minutes, code changes to No. 13. Check for: • Blower motor failure. • Motor start capacitor. • Open flame rollout switch,
manual reset.
• Dirty filter. • Defective limit switch or
connections.
• Loose blower wheel.
34 IGNITION PROVING FAILURE -
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 ignition period, blower will come on for 90-sec recycle delay. Check for the following items first before proceding to the next step. • Gas valve turned off. • Manual shut-off valve. • Green wire must be connected
to furnace sheet metal.
To determine whether the problem is in the gas valve, ignitor, or flame sensor, the 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?
Check for:
• Inadequate flame carryover on
rough ignition.
• Low inlet gas pressure.
NO
YES
YES YES YES YES YES
YES YES YES
NO NO
NO NO NO NO NO
•Inadequate combustion air
supply (flame rollout switch only).
NO
—11—

A94328
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
© 2000 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231 —12— Printed in U.S.A. sp04-61 Catalog No. 5339-307