Watts AERCO Edge CFR 3000 Operator's And Service Manual page 52

SECTION 9 TROUBLESHOOTING
TABLE 9-1: Boiler Troubleshooting Procedures
Fault Probable Causes
Worn Flame Detector or cracked
1.
ceramic.
Defective Regulator.
2.
FLAME LOSS
DURING RUN Poor combustion calibration.
3.
Debris on burner.
4.
Blocked condensate drain.
5.
The Heat Demand Relays on the
1.
Ignition/Stepper (IGST) board failed
HEAT DEMAND
to activate when commanded.
FAILURE
Relay is activated when not in
2.
Demand.
Poor combustion calibration.
1.
HIGH EXHAUST
TEMPERATURE Carboned heat exchanger due to
2.
incorrect combustion calibration.
Incorrect supply gas pressure.
1.
Defective SSOV Actuator.
2.
HIGH GAS
PRESSURE
Defective High Gas Pressure switch.
3.
Faulty Water temperature switch.
1.
Incorrect PID settings.
2.
HIGH WATER
TEMP SWITCH
OPEN
Faulty shell temperature sensor.
3.
Unit in Manual mode.
4.
•
Corrective Action
Remove and inspect the Flame Detector for signs
1.
of wear or cracked ceramic. Replace if necessary.
Check gas pressure readings using a gauge or
2.
manometer into and out of the Air/Fuel Valve to
ensure that the gas pressure into and out of the
valve is correct.
Check combustion calibration using the
3.
procedures in Section 4.4: Combustion
Calibration of this guide.
Remove the burner and inspect for any carbon
4.
build-up or debris. Clean and reinstall.
Remove blockage in condensate drain.
5.
Press CLEAR button and restart the unit. If the
1.
fault persists, replace Ignition/Stepper (IGST)
Board.
Defective relay. Replace IGST Board.
2.
Check combustion calibration using procedures
1.
in Section 4.4: Combustion Calibration of this
guide.
If exhaust temperature is greater than 200
2.
o
(93.3 C), check combustion calibration. Calibrate
or repair as necessary.
Check to ensure gas pressure at inlet of SSOV
1.
does not exceed 14" W.C. (3.49 kPa).
If gas supply pressure downstream of SSOV
2.
Actuator cannot be lowered to the range
specified in Table 4-1 (Natural Gas) in Section 4.4:
Combustion Calibration of this guide; the SSOV
Actuator may be defective.
Remove the leads from the High Gas Pressure
3.
switch. Measure continuity across the common
(C) and normally closed (NC) terminals with the
unit not firing. Replace the switch if continuity
does not exist.
Test the temperature switch to insure it trips at
1.
its actual water temperature setting.
Check PID settings (Advanced Setup à
2.
Performance à Temperature Control, first 3
items). If the settings have been changed, record
the current readings then reset to default values.
Using the resistance charts in the manual to
3.
measure the resistance of Shell sensor and BTU
sensor at a known water temperature.
If unit is in Manual mode, switch to Auto mode
4.
(Diagnostic à Manual Mode).
• •
o
F