AERCO KC1000 Low NOx Boiler equipped with C-More version 3.04 - Manual (Page 64)

TROUBLESHOOTING
8 -4
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
FLAME LOSS
DURING RUN
1. Worn Flame Detector or cracked
ceramic.
2. Defective Differential Regulator.
3. Poor combustion calibration.
4. Debris on burner.
5. Blocked condensate drain.
1. Remove and inspect the Flame Detector for signs of wear or
cracked ceramic. Replace if necessary.
2. Check gas pressure readings using a gauge or manometer into
and out of the Air/Fuel Valve to ensure that the gas pressure
into and out of the valve is correct.
3. Check combustion calibration. Adjust as necessary.
4. Remove the burner and inspect for any carbon or debris. Clean
and reinstall.
5. Remove blockage in condensate drain.
HEAT DEMAND
FAILURE
1. The Heat Demand Relays on the
Ignition/Stepper board failed to
activate when commanded
2. Relay is activated when not in
Demand
1. Press CLEAR button and restart the unit. If the fault persists,
replace Ignition/Stepper (IGST) Board.
2. Defective relay. Replace IGST Board.
HIGH EXHAUST
TEMPERATURE 1. Defective exhaust sensor.
2. Carboned heat exchanger due to
incorrect combustion calibration
1. Measure the actual exhaust temperature and continuity of the
exhaust sensor. If the exhaust temperature is less than 475
°
F
and the exhaust sensor shows continuity replace the sensor.
2. If exhaust temperature is greater than 500
°
F, check combustion
calibration. Calibrate or repair as necessary.
HIGH GAS
PRESSURE
1. Incorrect supply gas pressure.
2. Defective Supply Regulator or
Wrong Style Regulator
3. Defective High Gas Pressure Switch
1. If using a non-lock up style regulator for the gas supply,
measure static gas pressure downstream, it should be 14”WC
or less. Adjust as necessary.
2. If gas supply pressure cannot be lowered, a lock-up style
regulator may be required or the supply regulator may be
defective.
3. Remove the leads from the high gas pressure switch. Measure
continuity across the common and normally closed terminals
with the unit not firing. Replace the switch if it does not show
continuity.