AERCO BMK 3.0 LN Nat. Gas Jan 2011 - Manual (Page 67)

TROUBLESHOOTING
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 c ontact with the c am,
check to ens ure that the s witch 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 ver ify it is blinking ON & O FF
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 r otate, c heck the purge switch for
continuity w hen c losing. Replac e s witch if c ontinuity does not
exist.
2. Measure for 24 VAC f rom each side of the s witch to gr ound. If
24VAC is not present, refer fault to qualified service personnel.
3. Check to ens ure that the s witch is w ired c orrectly (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 ver ify it is blinking ON & O FF
every second. If not, replace IGST Board.
OUTDOOR TEMP
SENSOR FAULT
1. Loose or broken wiring.
2. Defective Sensor.
3. Incorrect Sensor.
1. Inspect Outdoor Temperature sensor for loose or broken wiring.
2. Check resistance of sensor to determine if it is within
specification.
3. 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.
3. Control Box signal type selection
switches not set for correct signal
type (voltage or current).
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.
3. Check DIP switch on PMC board to ensure it is set correctly for
the type of signal being sent. Check control signal type set in
Configuration Menu.
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