Lang GCCO-T - Page 53

53
TROUBLESHOOTING GCCO-PP / -PT CONT’D
NO HEAT, MANUAL MODE
PROBABLE CAUSE CORRECTIVE ACTION
Defective back-up toggle
switch
 Confirm that toggle switch is in the “ON” position.
 Check toggle switch for normal operation.
Defective back-up relay
 Check for 120VAC at relay coil.
If no voltage is present:
 Confirm that points are making.
If voltage is present:
 Replace relay.
Defective component
transformer
 Confirm that 120VAC is feeding primary coil.
 Confirm that 24VAC is at secondary coil.
Failed Ignition
 See Failed Ignition portion of this manual.
 Check for 24VAC at MV on the spark modual to ground.
If no voltage is present:
 Confirm that pilot is lit.
 Replace as necessary.
If voltage is present:
 Check thermostat for normal operation.
Defective Thermostat
 Confirm that thermostat has 24VAC.
If no voltage is present
 Check component transformer and wiring for normal operation.
If voltage is present
 Check thermostat for normal operation. Replace as necessary.
Defective centrifugal switch in
motor
 Disconnect centrifugal switch and check of continuity while the
motor is running.
If no continuity is present:
 Replace motor.
If continutiy is present:
 Check thermostat for normal operation.
 Check wires
Defective main valve
 Check for 24VAC across valve.
If no voltage is present:
 Confirm that wires have continuity.
If voltage is present:
 Replace valve.