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TROUBLESHOOTING
FAULT INDICATION
continued
2. Defective or shorted switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or
5. Defective IGST Board
PRG SWTCH OPEN
1. Defective purge switch.
DURING PURGE
2. No voltage present at switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or
5. Defective IGST Board
OUTDOOR TEMP
1. Loose or broken wiring.
SENSOR FAULT
2. Defective Sensor.
6. Incorrect Sensor.
REMOTE SETPT
1. Remote setpoint signal not present:
SIGNAL FAULT
2. Signal is not isolated (floating) if 4 to
-8
8
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
PROBABLE CAUSES
fuse
fuse
Not yet installed.
Wrong polarity.
Signal defective at source.
Broken or loose wiring.
20 mA.
CORRECTIVE ACTION
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.
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.
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.
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.
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