Code

Error Code Table

Code	Fault	Remedy

14	Thermal Fuse	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 build-
		up. 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.
16	Over Temperature	Check for restrictions in air flow around unit and vent terminal.
	Warning	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.
32	Outgoing Water	Check sensor wiring for damage.
	Temperature Sensor	Measure resistance of sensor.
	Fault	Clean sensor of scale build-up.
		Replace sensor.
33	Heat Exchanger	Check sensor wiring for damage.
	Outgoing Temperature	Measure resistance of sensor.
	Sensor Fault	Clean sensor of scale build-up.
		Replace sensor.
34	Combustion Air	Check for restrictions in air flow around unit and vent terminal.
	Temperature Sensor	Check sensor wiring for damage.
	Fault	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.
52	Modulating Solenoid	Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
	Valve Signal Abnormal	Measure resistance of valve coil.
61	Combustion Fan	Ensure fan will turn freely.
	Failure	Check wiring harness to motor for damaged and/or loose connections.
		Measure resistance of motor winding.
71	SV0, SV1, SV2, and	Check wiring harness to all solenoids for damage and/or loose connections.
	SV3 Solenoid Valve	Measure resistance of each solenoid valve coil.
	Circuit Fault
72	Flame Sensing Device	Ensure flame rod is touching flame when unit fires.
	Fault	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.
LC	Scale Build-up in Heat	Flush heat exchanger. Refer to instructions in manual.
	Exchanger (when	Replace heat exchanger.
	checking maintenance
	code history, “00” is
	substituted for “LC”)
No	Nothing happens when	Clean inlet water supply filter.
code	water flow is activated.	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 is
		flowing, 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.

10		305, 505, 705 Indoor Manual

Error Code Table

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