A.O. Smith PCG2J4040T3NOV 100, PCG6240T403NOV 100, GAHH 40 100 manual LDO-SW, OPEN, and Clean Screen

CONTROL DISPLAY TROUBLESHOOTING

	CONTROL DISPLAY STATUS	PROBLEM	SOLUTION
9.	“FV-SENSE” Flashing		4. System must be manually reset by entering a
	(Continued from previous page)		special FVS reset sequence into the Electronic
			Control Display. See Electronic Control
			Display - FV - Sense Reset Sequence for
			instructions. It is also recommended that the
			FV Sensor be replaced.
10.	“LDO-SW”, “OPEN”, and “CLEAN SCREEN”	The air pressure switch contacts	1. Clean the screen on the combustion air
	Flashing	remain open longer than 5	intake chamber, retest.
		seconds after the combustion fan	2. If the problem persists: Cycle power to the
		is energized.
			water heater “OFF” and “ON” to reset.
11.	“FV-SENSE” and “OPEN” Flashing		1. Check all wiring to the flammable vapor
		Flammable Vapor Sensor is open	sensor.
			2. Remove the connectors from the
			flammable vapor sensor and measure
			the resistance of the sensor with an
			ohmmeter.
			A. If the reading taken is more than
			1.7 million ohms, replace the
			flammable vapor sensor.
			B. If the reading taken is less than 1.7
			million ohms, and the wiring from
			the control to the sensor is good,
			replace the lower control.
			1. Check all wiring to the flammable vapor
12.	“FV-SENSE” and “SHORT” Flashing	Flammable Vapor Sensor is	sensor.
		shorted	2. Remove the connectors from the
			flammable vapor sensor and measure
			the resistance of the sensor with an
			ohmmeter.
			A. If the reading taken is less than
			2000 ohms, replace the flammable
			vapor sensor.
			B. If the reading taken is more than
			2000 ohms, and the wiring from the
			control to the sensor is good,
			replace the lower control.
13.	“THMSTR” and “OPEN” Flashing		1. Turn power off for 10 to 20 seconds then
		The self-diagnostic test has	on again to clear this error code.
		detected the temperature sensor	2. This part of the control cannot be
		(thermistor) inside the immersion
		probe is open.	replaced or serviced. If the error code
			cannot be cleared, the lower control must
			be replaced.
14.	“THMSTR” and “SHORT” Flashing	The self-diagnostic test has	1. Turn power off for 10 to 20 seconds then
			on again to clear this error code.
		detected the temperature sensor	2. This part of the control cannot be
		(thermistor) inside the immersion
		probe is shorted.	replaced or serviced. If the error code
			cannot be cleared, the lower control must
			be replaced.
15.	All Segments Flashing	The self-diagnostic check has	1. Press and release each of the
			temperature adjustment buttons. If the
		detected one or both of the	above action does not clear the error, the
		temperature adjustment buttons	control will continue to regulate the water
		are stuck.	temperature at the last setting. However,
			settings will no longer be adjustable – the
			upper control should be replaced.
			1. Check the wire that runs from the power
16.	“P-ANODE” and “OPEN” Flashing	No current to Power Anode.	anode to the upper control. Check the
			wire for damage, and to ensure that the
			connectors are fully seated into the
			mating connectors on both ends.
			2. Check that the tank is full of water. Never
			use this water heater unless it is
			completely full of water. To prevent
			damage to the tank, the tank must be
			filled with water. Water must flow from
			the hot water faucet before turning “ON”
			gas to the water heater.
			3. Cycle power to the water heater “OFF” and
			“ON” to reset.
17.	“P-ANODE” Flashing		1. Turn the power off for 10 to 20 seconds
		Power Anode circuit failure.	then on again to clear the error code.
			2. If the error code persists or cannot be
			cleared, replace the upper control.

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