Mitsubishi Electronics MSZ-FA25VA, MSZ-FA35VA service manual Troubleshooting check table

9-4. Troubleshooting check table

Lighted

· Flashing of POWER lamp indicates abnormalities.

Blinking

Not lighted

NOTE : Before taking measures, make sure that the symptom reappears for accurate troubleshooting. Self check table

No.	Abnormal	Operation indicator lamp	Symptom	Detection method	Check point
	point
		POWER lamp flashes.
	Mis-Wiring	0.5-second ON	Outdoor unit	When the serial signal form the outdoor unit is	• Refer to 9-6.D"How to check
1	or serial		does not		mis-wiring and serial signal
				not received for a maximum of 6 minutes.
	signal		operate.		error".
		0.5-second OFF
	Outdoor			When it cannot properly read data in the	• Check the blinking pattern of
			Outdoor unit		the LED on the inverter P.C.
2	control	POWER lamp lights up		nonvolatile memory of the inverter P.C. board	board or the outdoor lectronic
			does not	or the outdoor electronic control P.C. board.
	system				control P.C. board.
			operate.
	Indoor coil	POWER lamp flashes.
	thermistor
		2-time flash	Indoor unit	When the indoor coil or the room temperature	• Refer to 9-7.the
3			and outdoor	thermistor is short or open circuit.	characteristics of indoor coil
	Room		unit do not		thermistor, and the room
	tempera-	2.5-second OFF	operate.		temperature thermistor.
	ture
	thermistor
		POWER lamp flashes.	Indoor unit
		3-time flash		When the rotational frequency feedback	• Refer to 9-7.A"Check of
	Indoor fan		and outdoor
4				signal is not emit during the indoor fan
	motor		unit do not		indoor fan motor".
				operation.
			operate.
		2.5-second OFF
		POWER lamp flashes.	Indoor unit	When it consecutively occurs 3 times that the	• Refer to "Check of inverter/
	Outdoor	5-time flash
					compressor".
5	power		and outdoor	compressor stops for overcurrent protection or	Refer to service manual
			unit do not	start-up failure protection witth in 1 minute
	system				OB372 or OB377.
			operate.	after start-up.
		2.5-second OFF			Check the stop valve.
		POWER lamp flashes.
		6-time flash	Indoor unit	When the outdoor thermistors short or open	• Refer to "Check of outdoor
	Outdoor		and outdoor		thermistor".
6			unit do not	circuit during the compressor operation.	Refer to service manual
	thermistors
			operate.		OB372 or OB377.
		2.5-second OFF
		POWER lamp flashes.	Indoor unit		• Replace the inverter P.C.
	Outdoor	7-time flash		When it cannot properly read data in the	board or the outdoor
			and outdoor
7	control			nonvolatile memory of the inverter P.C. board	electronic control P.C. board.
			unit do not
	system			or the outdoor electronic control P.C. board.	Refer to service manual
			operate.
		2.5-second OFF			OB372 or OB377.
		POWER lamp flashes.	Indoor unit
	Other	14-time flash		An abnormality other than above mentioned is	• Confirm the abnormarity in
8			and outdoor		detail using the failure mode
	abnonmality		unit do not	deteced.
			operate.		recall function.
		2.5-second OFF

NOTE : When the indoor unit has started operation and the above detection method has detected an abnormality (the first detection after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with OPERATION INDICATOR lamp flashing.

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