Watts AERCO Benchmark 2.0LN, Operating & Maintenance Instructions

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TROUBLESHOOTING
8
-8
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
continued 2. Defective or shorted switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or
fuse
5. Defective IGST Board
2. If the Air/Fuel Valve does rotate to the ignition position, check
the 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).
3. 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.
PRG SWTCH OPEN
DURING PURGE
1. Defective purge switch.
2. No voltage present at switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or
fuse
5. Defective IGST Board
1. If the air-fuel valve does rotate, check the purge switch for
continuity when closing. Replace switch if continuity does not
exist.
2. Measure for 24 VAC from each side of the switch to ground. If
24VAC is not present, refer fault to qualified service personnel.
3. Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals).
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.
OUTDOOR TEMP
SENSOR FAULT
1. Loose or broken wiring.
2. Defective Sensor.
6. Incorrect Sensor.
1. Inspect Outdoor Temperature sensor for loose or broken wiring.
2. Check resistance of sensor to determine if it is within
specification.
6. Ensure that the correct sensor is installed.
REMOTE SETPT
SIGNAL FAULT
1. Remote setpoint signal not present:
Not yet installed.
Wrong polarity.
Signal defective at source.
Broken or loose wiring.
2. Signal is not isolated (floating) if 4 to
20 mA.
1. Check I/O Box to ensure signal is hooked up.
Hook up if not installed.
If installed, check polarity.
Measure signal level.
Check continuity of wiring between source and boiler.
2. Check signal at source to ensure it is isolated.