Lang GCCO-T Service Manual page 40

PROBABLE CAUSE
Igniter continues to spark after
pilot is lit
Defective Module
Defective Isolation Transformer
Defective Door switch
Defective Motor relay
Defective Motor
NO HEAT
NOTE: The motor needs to be operational before the oven will start heating.
PROBABLE CAUSE
Defective Probe
Defective Circuit board
Defective Centrifugal Switch
Defective Hi Limit Thermostat
Defective Solenoid Valve
Plugged Main Burner Orifice
TROUBLESHOOTING GCCO-AP
CORRECTIVE ACTION
Check pilot for strong flame and good contact with sensor.
Check sense wire for 12 to 13 micro amps on spark module. (Johnson
Control spark modules use "#4" terminal and Channel spark modules
use "Sense" terminal).
Turn oven off and check sense wire for continuity.
Replace sense wire or spark module as necessary.
Confirm that there is a pilot ignition.
Check for 24VAC at "MV" to ground.
Confirm that transformer is getting voltage.
Check transformer for normal operation.
Confirm that Door switch is getting voltage.
Check door switch for normal operation.
Confirm that motor relay is getting power.
Check motor relay for normal operation. (24 VAC 39 Ω)
Confirm that motor is getting power.
Check motor for normal operation. (HIGH: P1-T7,T4) (LOW: P1-T9)
CORRECTIVE ACTION
Confirm that probe is operating properly. (See Technical Data)
Confirm that Heat Call light is on.
If no light is detected:
Check 12-position switch for normal operation. (See Technical Data)
If light is detected:
Check for 24VAC across heat output and "D" on 12 Pole terminal.
If voltage is not present:
Replace Circuit board.
If voltage is present:
Check over temperature thermostat for proper operation.
Check door switch for normal operation.
Confirm that when motor is running that there is continuity through
Centrifugal switch.
Check Hi Limit Thermostat for continuity.
Confirm that Valve is getting voltage.
Check Valve for normal operation.
Clean orifice.
40