Watts AERCO Benchmark BMK750 Operation And Service Manual page 153

Benchmark with Edge [I]: Operation-Maintenance Manual
SECTION 9 – TROUBLESHOOTING
TABLE 9-1: Boiler Troubleshooting Procedures
Fault Probable Causes
Defective Power Supply Board
4.
or fuse.
Defective IGST Board.
5.
Defective Purge switch.
1.
No voltage present at switch.
2.
PRG
Switch wired incorrectly.
3.
SWTCH
OPEN
DURING
PURGE
Defective Power Supply Board
4.
or fuse.
Defective IGST Board.
5.
Loose or broken wiring.
1.
OUTDOOR
TEMP
Defective Sensor.
2.
SENSOR
FAULT
Incorrect Sensor.
3.
Internal recirculation pump
1.
RECIRC
failed.
PUMP
FAILURE
1. Remote setpoint signal not
present:
•
Not yet installed.
REMOTE
•
Wrong polarity.
SETPT
•
Signal defective at source.
SIGNAL
•
Broken or loose wiring.
FAULT
Signal is not isolated (floating) if
2.
4 to 20 mA.
OMM-0145_A99 • GF-218 • Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
9/18/2019
Corrective Action
Check DS1 & DS2 LEDs on Power Supply
4.
Board. If they are not steady ON, replace
Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is
5.
blinking ON & OFF every second. If not,
replace IGST Board.
If the air-fuel valve does rotate, check Purge
1.
switch for continuity when closing. Replace
switch if continuity does not exist.
Measure for 24 VAC from each side of the
2.
switch to ground. If 24VAC is not present,
refer fault to qualified service personnel.
Check to ensure that the switch is wired
3.
correctly (correct wire numbers on the
normally open terminals).
Check DS1 & DS2 LEDs on Power Supply
4.
Board. If they are not steady ON, replace
Power Supply Board.
Check "Heartbeat" LED DS1 and verify it is
5.
blinking ON & OFF every second. If not,
replace IGST Board.
Inspect Outdoor Temperature sensor for loose
1.
or broken wiring.
Check resistance of sensor to determine if it is
2.
within specification.
Ensure that the correct sensor is installed.
3.
1. Replace recirculation pump.
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 unit.
Check signal at source to ensure it is isolated.
2.
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