Watts AERCO CFR 1500 Operation And Service Manual page 52

SECTION 9 TROUBLESHOOTING
TABLE 9-1: Boiler Troubleshooting Procedures
Fault Probable Causes
Remote setpoint signal not
present:
Not yet installed.
Wrong polarity.
Signal defective at source.
Broken or loose wiring.
REMOTE SETPT
SIGNAL FAULT Signal is not isolated (floating) if 4
to 20 mA.
Edge Controller signal type
selection switches not set for
correct signal type (voltage or
current).
Defective Flame Detector.
SSOV not fully closed.
RESIDUAL FLAME
Wire strand from burner head in
contact with Flame Detector
SSOV FAULT See SSOV SWITCH OPEN
DURING PURGE
SSOV FAULT SSOV switch closed for 15 seconds
DURING RUN during run.
SSOV relay failed on IGST board.
Floating Neutral.
SSOV RELAY
FAILURE
Hot and Neutral reversed at SSOV.
Actuator not allowing for full
closure of gas valve.
SSOV powered when shouldn't be
SSOV SWITCH
OPEN
Defective switch or Actuator.
Incorrectly wired switch.
Air/Fuel Valve unplugged.
Loose wiring connection to the
stepper motor.
Defective Air/Fuel Valve stepper
STEPPER MOTOR motor.
FAILURE Defective Power Supply
Board/fuse.
Defective IGST Board.
Air/Fuel Valve out of calibration
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Corrective Action
Check I/O Box to ensure signal is hooked up.
Hook up if not installed.
If installed, check polarity.
Measure signal level.
Check continuity of wiring between source and unit.
Check signal at source to ensure it is isolated.
Check DIP switch on PMC board to ensure it is set correctly for
the type of signal being sent. Check control signal type set in
the Remote Signal parameter (Advanced Setup > Unit >
Application Configuration).
Replace Flame Detector.
Check open/close indicator window of Safety Shut-Off Valve
(SSOV) and ensure that the SSOV is fully closed. If not fully
closed, replace the valve and or actuator.
Close the Gas Shut-Off Valve downstream of SSOV. Install a
manometer or gauge at the leak detection port between the
SSOV and Gas Shut Off Valve. If a gas pressure reading is
observed replace the SSOV Valve and/or Actuator.
Ensure Flame Detector is in good condition and is not tilted
inward toward burner head.
Replace actuator.
Press CLEAR button and restart unit. If fault persists, replace
Ignition/Stepper (IGST) Board.
The Neutral and Earth Ground are not connected at the source
and therefore there is a voltage measured between the two.
Normally this measurement should be near zero or no more
than a few millivolts.
Check SSOV power wiring.
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.
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.
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.
Ensure SSOV Proof of Closure switch is correctly wired.
Check Air/Fuel Valve is connected to the Edge Controller.
Inspect for loose connections between the Air/Fuel Valve
motor and the wiring harness.
Replace stepper motor.
Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
Perform stepper motor calibration procedure
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