AERCO C-More Controls - Manual (Page 68)

APPENDIX B
TABLE B-2. KC1000 WATER HEATER TROUBLESHOOTING TABLE – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
SSOV FAULT
DURING PURGE
1. See SSOV SWITCH OPEN
SSOV FAULT
DURING RUN
1. SSOV switch closed for 15 seconds
during run.
1. Replace or adjust microswitch in SSOV actuator. If fault
persists, replace actuator.
SSOV RELAY
FAILURE
1. SSOV relay failed on board. 1. Press CLEAR button and restart unit. If fault persists, replace
Ignition/Stepper (IGST) Board.
SSOV
SWITCH OPEN
1. Actuator not allowing for full closure
of gas valve
2. SSOV powered when it should not
be
3. Defective Switch or Actuator
4. Incorrectly wired switch.
1. Observe operation of the Safety Shut-Off Valve (SSOV) through
indicator on the Valve actuator and ensure that the valve is fully
and not partially closing.
2. If the SSOV never closes, it may be powered continuously.
Close the gas supply and remove power from the unit. Refer
fault to qualified service personnel.
3. Remove the electrical cover from the SSOV and check switch
continuity. If the switch does not show continuity with the gas
valve closed, either adjust or replace the switch or actuator.
4. Ensure that the SSOV Proof of Closure switch is correctly wired.
STEPPER MOTOR
FAILURE
1. Air/Fuel Valve out of calibration.
2. Air/Fuel Valve unplugged.
3. Loose wiring connection to the
stepper motor.
4. Defective Air/Fuel Valve stepper
motor.
5. Defective Power Supply Board or
fuse
6. Defective IGST Board
1. Perform Stepper Test (para. 6.3.5) to ensure stepper motor
rotates properly between the 0% (fully closed) and 100% (fully
open) positions. Verify that the FIRE RATE bargraph and the
dial on the Air/Fuel Valve track each other to indicate proper
operation. If operation is not correct, perform the Stepper
Feedback Calibration (para. 6.2.1).
2. Check to ensure that the Air/Fuel Valve is connected to the
Control Box.
3. .Inspect for loose connections between the Air/Fuel Valve motor
and the wiring harness.
4. Replace stepper motor.
5. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
6. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
B-18