Watts AERCO Benchmark BMK5000 Operation And Service Manual page 139

Benchmark Platinum-Edge [ii]: Operation-Service Manual
SECTION 6 – TROUBLESHOOTING
TABLE 10-1: Boiler Troubleshooting Procedures
Fault Probable Causes
A/F Valve rotated open to purge and did not
1.
rotate to ignition position.
Defective or shorted switch.
2.
PRG SWTCH
CLOSED
DURING
IGNITION
Switch wired incorrectly.
3.
4. Defective Power Supply Board or fuse.
Defective IGST Board.
5.
Defective Purge switch.
1.
No voltage present at switch.
2.
PRG SWTCH
Switch wired incorrectly.
3.
OPEN DURING
PURGE
Defective Power Supply Board or fuse.
4.
Defective IGST Board.
5.
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12/20/2022
Corrective Action
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 Edge Controller.
Refer fault to qualified service personnel.
If the Air/Fuel Valve does rotate to the ignition position, check the
2.
purge switch for continuity between the N.O. and COM terminals.
If the switch shows continuity when not in contact with the cam,
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.
3.
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
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.
If the air-fuel valve does rotate, check Purge switch for continuity
1.
when closing. Replace switch if continuity does not exist.
Measure for 24 VAC from each side of the switch to ground. If
2.
24VAC is not present, refer fault to qualified service personnel.
Check to ensure that the switch is wired correctly (correct wire
3.
numbers on the normally open terminals).
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.
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