Bryant GAS-FIRED INDUCED-COMBUSTION FURNACES 373LAV Service And Maintenance Procedures Manual page 7

THREE-WIRE
HEATING-ONLY
BLOWER DOOR SWITCH
BLK BLK
WHT WHT
GND
AUXILIARY
115-V FIELD-
J-BOX
SUPPLIED
DISCONNECT
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 cooling speed for 10 sec, then
turns off.
e. Main blower operates at heating 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 "Com-
ponent 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.
NOTE 2
W C
FIVE WIRE
W
C
R
O
N
T
GND
R G
O
C
L
NOTE 1
Y
24-V
TERMINAL
BLOCK
NOTES:
FURNACE
Fig. 10—Heating and Cooling Application Wiring Diagram
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
THERMOSTAT
R G Y
TERMINALS
CONDENSING
UNIT
TWO
WIRE
1. Connect Y-terminal in furnace as shown for proper blower operation.
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.
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 diagnostic light),
and C
block. (See Fig. 11.)
NOTE: If TEST to C
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.
E. Troubleshooting
Refer to the service label. (See Fig. 13.) Pages 10 and 11 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.
—7—
FIELD-SUPPLIED
DISCONNECT
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
GND
-24V terminal on furnace thermostat connection
OM
-24V terminals are jumpered longer than
OM
A98521