AERCO BMK 2.0 LN Dual Fuel Serial G-11-2402 and UP - Manual (Page 87)

CHAPTER 8: TROUBLESHOOTING GUIDE
PR2: 04/22/13 Page 87 of 160
Benchmark 2.0LN Dual-Fuel Low NOx Boiler
Operation and Maintenance Manual
OMM-0052_0E
GF-127
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
FLAME LOSS
DURING IGN
(continued)
7. Unstable gas pressure.
8. Carbon or other debris on Burner.
9. Staged ignition solenoid valves don’t open.
10. Clogged staged ignition piece.
7. Refer to “Gas Pressure Requirements” section of GF-2030:
BMK Gas Supply Design Guide.
8. Remove the burner and inspect for any carbon or debris.
Clean and reinstall.
9. When boiler goes to ignition, listen to the solenoid valves
for a clicking sound to ensure they are opening.
10. Remove and inspect staged ignition piece for blockage.
FLAME LOSS
DURING RUN
1. Worn Flame Detector or cracked ceramic.
2. Defective Regulator.
3. Poor combustion calibration.
4. Debris on burner.
5. Blocked condensate drain.
1. Remove and inspect the Flame Detector for signs of wear or
cracked ceramic. Replace if necessary.
2. Check gas pressure readings using a gauge or manometer
into and out of the Air/Fuel Valve to ensure that the gas
pressure into and out of the valve is correct.
3. Check combustion calibration. Adjust as necessary.
4. Remove the burner and inspect for any carbon or debris.
Clean and reinstall.
5. Remove blockage in condensate drain.
HEAT DEMAND
FAILURE
1. The Heat Demand Relays on the
Ignition/Stepper board failed to activate when
commanded.
2. Relay is activated when not in Demand.
1. Press CLEAR button and restart the unit. If the fault
persists, replace Ignition/Stepper (IGST) Board.
2. Defective relay. Replace IGST Board.
HIGH GAS
PRESSURE
1. Incorrect supply gas pressure.
2. Defective gas pressure adjustment in SSOV
Actuator.
3. Defective High Gas Pressure Switch
4. Gas pressure snubber not installed.
5. Fluctuating supply gas pressure.
1. Check to ensure gas pressure at inlet of SSOV is 2 psig maximum.
2. If gas supply pressure downstream of SSOV Actuator cannot be
lowered, to 2.8” W.C. (or 2.3” W.C. for propane), using the gas
pressure adjustment screw (see para. 4.3, step 10), the SSOV
Actuator gas pressure adjustment mechanism may be defective.
See para. 4.3, Step 10 (nat. gas) or 4.4, Step 10 (propane).
3. Remove the leads from the high gas pressure switch and measure
continuity across the common and normally closed terminals with
the unit not firing. Replace the switch if it does not show continuity.
4. See Figure 8-1. Ensure that the gas pressure snubber is installed at
the high gas pressure switch.
5. Measure gas pressure upstream of SSOV and monitor for
sudden changes (see Fig. 8-1).