Bryant 333B-AV-036060-AA-JA, Troubleshooting Manual

Page: 14 / 46

STEP ACTION YES NO GO TO
26.
Replace capacitor. If problem still exists after replacing capacitor, replace
blower motor.
— — 8
27.
Replace blower motor. If problem still exists after replacing blower motor, re-
place capacitor.
— — 8
28. Does furnace have a variable-speed ICM blower motor? 30 29 —
29.
Lockout was caused by excessive return-air restriction. Check filter and return-
air grilles for blockage. Add more return-air openings if necessary. Use Appen-
dix E to evaluate external static pressure.
— — 8
STEP TERMINAL CONNECTIONS* VOLTAGE ACTION
30.
HUM
WHITE (+)
to
C
OM
-24V
(-)
24 vac
If voltages are correct, go to Step 31. If not, replace 2-stage
furnace control.
31.
PL9-2
WHITE (+)
to
PL9-3
BLACK (-)
24 vac
If voltages are correct, go to Step 32. If not, repair or replace
ICM blower harness.
STEP ACTION YES NO GO TO
32.
Make sure blower off delay is set to 135 sec or more, then disconnect W/W1
thermostat lead from 2-stage furnace control.
— — 33
33.
Does blower motor change speed 90 sec after W/W1 thermostat lead was dis-
connected from 2-stage furnace control.
29 34 —
34. Replace ICM blower motor. — — 8
* (+) and (-) designate Volt Ohm Meter Leads
Status Code 14
IGNITION LOCKOUT—THIS STATUS CODE INDICATES FURNACE FAILED TO IGNITE GAS AND/OR PROVE FLAME IN 4
ATTEMPTS. THE 2-STAGE FURNACE CONTROL WILL AUTO-RESET IN 3 HR. REFER TO STATUS CODE 34.
Status Code 21
GAS HEATING LOCKOUT—THIS STATUS CODE INDICATES MAIN GAS VALVE RELAY MGVR ON 2-STAGE FURNACE
CONTROL IS STUCK CLOSED, OR THERE IS A MISWIRE/SHORT TO GAS VALVE WIRING. THE 2-STAGE FURNACE
CONTROL WILL NOT AUTO-RESET.
STEP ACTION YES NO GO TO
1. Turn power off and set thermostat to OFF position. Then turn power back on. — — 2
2. Does status code 21 flash? 3 6 —
3. There is a miswire or short to gas valve wiring. — — 4
4. Fix problem. — — 5
5.
Go to page number indicated in Index for CLEANUP AND START-UP IN-
STRUCTIONS.
— — INDEX
6. Does a different status code flash? 7 8 —
7. Go to page number indicated in Index for section covering the status code. — — INDEX
8.
Remove blower door and depress door switch. Use a piece of tape to hold
switch closed.
— — 9
9. Jumper R and W/W1 thermostat terminals. — — 10
10. Does status code 21 start flashing when low-heat pressure switch LPS makes? 11 12 —
11. Replace 2-stage furnace control. — — 5
12. Does a different status code flash? 7 13 —
13.
Disconnect jumper wire across R and W/W1 thermostat terminals and wait until
blower stops.
— — 14
14. Jumper R, W/W1, and W2 thermostat terminals on 2-stage furnace control. — — 15
15.
Does status code 21 start flashing when high-heat pressure switch HPS
makes?
16 17 —
16. Replace gas valve. — — 5
17. Cycle furnace several times to check for intermittent operation. — — 18
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