AERCO KC Series Equipped with C-More version 3.04 - Manual (Page 76)

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 VALVE POSITION 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.