Instruction Manual

Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 8 – TROUBLESHOOTING GUIDE
Page 112 of 192 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0082_0J
05/21/2014 Ph.: 800-526-0288 GF-130
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
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 (C-More O & M) and perform the Stepper
Feedback Calibration procedure in Section 6, section 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.