AERCO BMK 1.5 LN July 2011 - Manual (Page 89)

CHAPTER 7: MAINTENANCE
PR2: 05/09/12 Page 89 of 152
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
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
IGN BOARD
COMM FAULT
1. Communication fault has occurred
between the PMC board and
Ignition/Stepper (IGST) board
1. Press CLEAR button and restart unit. If fault persists, contact
qualified Service Personnel.
IGN SWTCH CLOSED
DURING PURGE
1. Air/Fuel Valve not rotating
2. Defective or shorted switch
3. Switch wired incorrectly
4. Defective Power Supply Board or
fuse
5. Defective IGST Board
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position. If the valve does not rotate at all or does not
rotate fully open, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air-Fuel Valve or
the Control Box. Refer to qualified service personnel
2. . If the Air/Fuel Valve does rotate to purge, check the ignition
switch for continuity between the N.O. and COM terminals. If the
switch shows continuity when not in contact with the cam replace
the switch.
3. Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals). If the switch is wired
correctly, replace the switch
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
IGN SWTCH OPEN
DURING IGNITION
1. Air/Fuel Valve not rotating to
ignition position.
2. Defective ignition switch
3. Defective Power Supply Board or
fuse
4. Defective IGST Board
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position, then back to ignition position (towards closed)
during the ignition cycle. If the valve does not rotate back to the
ignition position, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air/Fuel Valve or
the Control Box. Refer fault to qualified service personnel.
2. If the Air/Fuel Valve does rotate to the ignition position, check the
ignition position switch for continuity between the N.O. and COM
terminals when in contact with the cam.
3. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
4. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.