Watts AERCO Benchmark OMM-0121 Operation And Maintenance Manual page 66

Benchmark 750-3000 Boiler Operation & Maintenance Manual
SECTION 5 – TROUBLESHOOTING GUIDE
TABLE 5-1: Boiler Troubleshooting Procedures
Fault
Probable Causes
Indication
Air/Fuel Valve not rotating.
1.
Defective or shorted switch.
2.
IGN SWTCH
CLOSED
DURING
PURGE Switch wired incorrectly.
3.
Defective Power Supply Board or fuse.
4.
Defective IGST Board.
5.
Air/Fuel Valve not rotating to ignition position.
1.
IGN SWTCH
OPEN
Defective Ignition switch.
2.
DURING
IGNITION
Defective Power Supply Board or fuse.
3.
Defective IGST Board.
4.
OMM-0122_D • GF-206 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
Corrective Action
Start the unit. The Air/Fuel Valve should rotate to the purge (open)
1.
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 C-More Controller.
Refer to qualified service personnel.
If the Air/Fuel Valve does rotate to purge, check the ignition switch
2.
for continuity between the N.O. and COM terminals. If the switch
shows continuity when not in contact with the cam replace the
switch.
Check to ensure that the switch is wired correctly (correct wire
3.
numbers on the normally open terminals). If the switch is wired
correctly, replace the switch.
Check DS1 & DS2 LEDs on Power Supply Board. If they are not
4.
steady ON, replace Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
5.
every second. If not, replace IGST Board.
Start the unit. The Air/Fuel Valve should rotate to the purge (open)
1.
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 C-More Controller.
Refer fault to qualified service personnel.
If the Air/Fuel Valve does rotate to the ignition position, check the
2.
ignition position switch for continuity between the N.O. and COM
terminals when in contact with the cam.
Check DS1 & DS2 LEDs on Power Supply Board. If they are not
3.
steady ON, replace Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is blinking ON & OFF
4.
every second. If not, replace IGST Board.
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