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Code Fault
14 Thermal Fuse
16
32
33
34
Over Temperature Warning
Outgoing Water Temperature Sensor
Fault
Heat Exchanger Outgoing Temperature
Sensor Fault
Combustion Air Temperature Sensor
Fault
Remedy
Check gas type of unit and ensure it matches gas type being used.
Check for restrictions in air flow around unit and vent terminal.
Check for low water flow in a circulating system causing short-cycling.
Ensure dip switches are set to the proper position.
Check for foreign materials in combustion chamber and/or exhaust piping.
Check heat exchanger for cracks and/or separations.
Check heat exchanger surface for hot spots which indicate blockage due to
scale buildup.
Refer to instructions in manual for flushing heat exchanger.
Measure resistance of safety circuit.
Ensure high fire and low fire manifold pressure is correct.
Check for improper conversion of product.
Check for restrictions in air flow around unit and vent terminal.
Check for low water flow in a circulating system causing short-cycling.
Check for foreign materials in combustion chamber and/or exhaust piping.
Check for clogged heat exchanger.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
Check for restrictions in air flow around unit and vent terminal.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Ensure fan blade is tight on motor shaft and is in good condition.
Replace sensor.
Check modulating gas solenoid valve wiring harness for loose or damaged
terminals.
Measure resistance of valve coil.
52 Modulating Solenoid Valve Signal
Abnormal
61 Combustion Fan Failure Ensure fan will turn freely.
Check wiring harness to motor for damaged and/or loose connections.
Measure resistance of motor winding.
65 Water Flow Control Fault If blank screen is present on remote control then the flow control has
shorted. Unplug flow control. If remote lights up and unit starts operating
then replace flow control assembly.
71 SV0, SVl, SV2, and SV3 Solenoid Valve Check wiring harness to all solenoids for damage and/or loose connections.
Circuit Fault Measure resistance of each solenoid valve coil.
72 Flame Sensing Device Fault
LC or
O0
Scale Build-up in Heat Exchanger (when
checking maintenance code history, "00"
is substituted for "LC")
Nothing happens when water flow is
activated.
No
Code
Ensure flame rod is touching flame when unit fires.
Check all wiring to flame rod for damage.
Remove flame rod and check for carbon build-up; clean with sand paper.
Check inside burner chamber for any foreign material blocking flame at
flame rod.
Measure micro amp output of sensor circuit with flame present.
Replace flame rod.
Flush heat exchanger. See Flushing the Heat Exchanger section.
Clean inlet water supply filter.
On new installations ensure hot and cold water lines are not reversed.
Check for bleed over.
Isolate unit from building by turning off hot water line to building.
Isolate the circulating system if present. Open your pressure relief
valve; if water isflowing, there is bleed over in your plumbing.
Ensure you have at least the minimum flow rate required to fire unit.
Ensure turbine spins freely.
Measure the resistance of the water flow control sensor.
Check for DC shorts at components.
30 305 & 505 Indoor Manual