Aerco Benchmark BMK 750 User Manual page 68

Benchmark 750-3000 Boiler Operation, Service, Maintenance Guide - KOREA
SECTION 5 – TROUBLESHOOTING GUIDE
TABLE 5-1: Boiler Troubleshooting Procedures
Fault
Probable Causes
Indication
SSOV relay failed on IGST board.
1.
Floating Neutral.
SSOV RELAY 2.
FAILURE
3. Hot and Neutral reversed at SSOV.
Actuator not allowing for full closure of gas
1.
valve.
SSOV powered when it should not be
2.
SSOV
SWITCH OPEN
Defective switch or Actuator.
3.
Incorrectly wired switch.
4.
Air/Fuel Valve out of calibration.
1.
Air/Fuel Valve unplugged.
2.
Loose wiring connection to the stepper motor.
3.
STEPPER
MOTOR
Defective Air/Fuel Valve stepper motor.
4.
FAILURE
Defective Power Supply Board or fuse.
5.
Defective IGST Board.
6.
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Corrective Action
Press CLEAR button and restart unit. If fault persists, replace
1.
Ignition/Stepper (IGST) Board.
The Neutral and Earth Ground are not connected at the source and
2.
therefore there is a voltage measured between the two. Normally this
measurement should be near zero or no more than a few millivolts.
3. Check SSOV power wiring.
Observe operation of the Safety Shut-Off Valve (SSOV) through
1.
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
2.
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.
Ensure that the SSOV Proof of Closure switch is correctly wired.
4.
Refer to the C-More User Manual OMM-0032 (GF-112) and perform
1.
the Stepper Feedback Calibration procedure in Section 6, Section
6.2.1.
2. Check that the Air/Fuel Valve is connected to the C-More
Controller.
Inspect for loose connections between the Air/Fuel Valve motor and
3.
the wiring harness.
Replace stepper motor.
4.
Check DS1 & DS2 LEDs on Power Supply Board. If they are not
5.
steady ON, replace Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
6.
every second. If not, replace IGST Board.
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
OMM-0128_0C
GF-206-K