AERCO BMK 2.0 LN Natural Gas (SN G-11-1861 and above) - Manual (Page 105)

GF-123
Benchmark 2.0LN Low NOx Boiler Chapter 8
OMM-0046_0E I nstallation, Operation and Maintenance Manual Troubleshooting
PR1 08/20/12 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 Page 105 of 170
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
RESIDUAL
FLAME
1. SSOV not fully closed.
2. Defective Flame Detector
1. 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 gas shut-off valve downstream of SSOV. Install a manometer
or gauge in a gas test port between the SSOV and the gas shut off
valve. If a gas pressure reading is observed replace the SSOV valve
and or actuator.2.
2. Replace Flame Detector.
SSOV FAULT DURING
PURGE
See SSOV SWITCH OPEN
SSOV FAULT
DURING RUN
1. SSOV switch closed for 15 seconds
during run.
1. Replace or adjust microswitch in SSOV actuator. If fault persists,
replace actuator.
SSOV RELAY
FAILURE
1. SSOV relay failed on board.
2. Floating Neutral.
3. Hot and Neutral reversed at SSOV.
1. Press CLEAR button and restart unit. If fault persists, replace
Ignition/Stepper (IGST) Board.
2. 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.
3. Check SSOV power wiring.
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 wire 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.