Kenmore 505, 305 owner manual Thermal Fuse, LC or

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 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.
16	Over Temperature Warning	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.
32	Outgoing Water Temperature Sensor	Check sensor wiring for damage.
	Fault	Measure resistance of sensor.

Clean sensor of scale build-up.

Replace sensor.

33Heat Exchanger Outgoing Temperature Check sensor wiring for damage.

	Sensor Fault			Measure resistance of sensor.
				Clean sensor of scale build-up.
				Replace sensor.
34	Combustion	Air Temperature Sensor		Check for restrictions in air flow around unit and vent terminal.
	Fault			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.
52	Modulating	Solenoid	Valve Signal	Check modulating gas solenoid valve wiring harness for loose or damaged
	Abnormal			terminals.
				Measure resistance of valve coil.
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.

71SV0, 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		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.
LC or	Scale Build-up in Heat				Exchanger	(when	Flush heat exchanger. See Flushing the Heat Exchanger		section.
O0	checking		maintenance		code history, "00"
	is substituted for			"LC")
No	Nothing		happens	when water		flow is	Clean inlet water supply filter.
Code	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.

28 305 & 505 Outdoor Manual