AERCO KC Series Equipped with C-More Controller for Massachusetts Only - Manual (Page 72)

TROUBLESHOOTING
7-9
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 SSOV actuator.
SSOV RELAY
FAILURE
1. SSOV relay failed on
board.
1. Ensure that Neutral and Earth Ground are connected
at the source and there is no voltage measured
between them. Measurement should indicate near
zero or no more than a few millivolts.
2. Check the SSOV power wiring.
3. 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. Refer to GF-112 and 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 (GF-112,
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.