Bryant GB1AAV, Service And Maintenance Instructions

Page: 13 / 16

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 recheck 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 and R-W closes.
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 and check for 115v between pins 1 and 2 on the board. Was there 115v present for the 17 sec period?
Replace control board.
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 board.
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 microamperes below 0.5?
Check connections and retry. If current is near typical value and control will not stay on, replace control board.
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 board.
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 board.
23
PRESSURE SWITCH WILL 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, DRAFT SAFEGUARD (WHEN USED), OR AUXILIARY LIMIT (WHEN USED) SWITCH WILL 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 igniton period, blower will come on for 90 sec recycle delay. Inadequate combustion air (for draft safeguard and auxiliary limit switches only).
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, igniter, or flame sensor, the system can be operated in the component test mode to check out the ignitor. First, remove the R thermostat connection from the control board 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 NO
• •
Inadequate combustion air supply (flame rollout switch only).
• •
A96218
—13—