AERCO BMK 3.0 LN Dual-Fuel Series Gas Fired Low NOx Boiler System - Manual (Page 72)

TROUBLESHOOTING
8-10
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
REMOTE SETPT
SIGNAL FAULT
(continued)
2. Signal is not isolated (floating) if 4 to
20 mA.
3. Control Box signal type selection
switches not set for correct signal
type (voltage or current).
2. Check signal at source to ensure it is isolated.
3. 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
Configuration Menu.
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. 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 IGST 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 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.