AERCO KC1000 Boiler July 2011 - Manual (Page 65)

TROUBLESHOOTING
8 -9
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
SSOV FAULT
DURING PURGE
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 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.