Troubleshooting check table | Mitsubishi Electronics MSY-A24NA

8-4. Troubleshooting check table

Before taking measures, make sure that the symptom reappears for accurate troubleshooting.

When the indoor unit has started operation and the following 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.

	Lighted	·Flashing of OPERATION INDICATOR lamp (left-hand side lamp)
OPERATION INDICATOR	Lighted	indicates abnormalities.
OPERATION INDICATOR	Blinking	indicates abnormalities.
	Blinking
	Not lighted

No.	Abnormal	Operation indicator lamp	Symptom	Condition	Correspondence
	point
		Left lamp flashes.	Indoor unit
	Mis-Wiring	0.5-second ON	Indoor unit		• Refer to 8-6.D"How to check
	Mis-Wiring		and outdoor	The serial signal from the outdoor unit is not	• Refer to 8-6.D"How to check
1	or serial		and outdoor	The serial signal from the outdoor unit is not	mis-wiring and serial signal
1	or serial		unit do not	received for a maximum of 6 minutes.	mis-wiring and serial signal
	signal		unit do not	received for a maximum of 6 minutes.	error".
	signal		operate.		error".
			operate.
		0.5-second OFF
	Outdoor				• Check the blinking pattern of
	control			It cannot properly read data in the nonvolatile	• Check the blinking pattern of
	system		Outdoor unit	It cannot properly read data in the nonvolatile	the LED on the inverter P.C.
	system			memory of the inverter P.C. board or the	the LED on the inverter P.C.
2	MSZ-A09/12	Left lamp lights up		memory of the inverter P.C. board or the	board or the outdoor
2	MSZ-A09/12	Left lamp lights up	does not	outdoor electronic control P.C. board.	board or the outdoor
	MSZ-A15/17		operate.		electronic
	MSZ-A15/17		operate.		control P.C. board.
	MSY-A15/17				control P.C. board.
	MSY-A15/17
	Indoor coil	Left lamp flashes.
	thermistor	Left lamp flashes.
	thermistor	2-time flash	Indoor unit	The indoor coil or the room temperature	• Refer to 8-7.the
		2-time flash	Indoor unit	The indoor coil or the room temperature	• Refer to 8-7.the
3			and outdoor	thermistor is short or open circuit.	characteristics of indoor coil
3	Room		unit do not		thermistor, and the room
	tempera-	2.5-second OFF	operate.		temperature thermistor.
	ture	2.5-second OFF
	ture
	thermistor
		Left lamp flashes.	Indoor unit
		3-time flash	Indoor unit	The rotational frequency feedback signal is	• Refer to 8-6.A"Check of
	Indoor fan		and outdoor	The rotational frequency feedback signal is
4	Indoor fan		and outdoor	not emitted during the indoor fan operation.
4	motor		unit do not	not emitted during the indoor fan operation.	indoor fan motor".
	motor		unit do not		indoor fan motor".
			operate.
		2.5-second OFF
	Indoor	Left lamp flashes.	Indoor unit	It cannot properly read data in the nonvolatile
		4-time flash	Indoor unit
		4-time flash	and outdoor		• Replace the indoor electronic
5	control		and outdoor	memory of the indoor electronic control P.C.	• Replace the indoor electronic
5	control		unit do not	memory of the indoor electronic control P.C.	control P.C. board.
	system		unit do not	board.	control P.C. board.
	system		operate.	board.
		2.5-second OFF	operate.
		2.5-second OFF
		Left lamp flashes.	Indoor unit	It consecutively occurs 3 times that the	• Refer to "How to check of
	Outdoor	5-time flash			• Refer to "How to check of
	Outdoor	5-time flash			inverter/ compressor".
6	power		and outdoor	compressor stops for overcurrent protection or	Refer to outdoor unit service
6	power		unit do not	start-up failure protection within 1 minute after	Refer to outdoor unit service
	system		unit do not	start-up failure protection within 1 minute after	manual.
	system		operate.	start-up.	manual.
		2.5-second OFF	operate.	start-up.	• Check the stop valve.
					• Check the stop valve.

		Left lamp flashes.
		6-time flash	Indoor unit	The outdoor thermistors short or open circuit	• Refer to "Check of outdoor
	Outdoor		and outdoor	The outdoor thermistors short or open circuit	thermistor".
7	Outdoor		unit do not	during the compressor operation.	Refer to outdoor unit service
7	thermistors		unit do not	during the compressor operation.	Refer to outdoor unit service
	thermistors		operate.		manual.
		2.5-second OFF	operate.		manual.
		2.5-second OFF
		Left lamp flashes.	Indoor unit		• Replace the inverter P.C.
	Outdoor	7-time flash	Indoor unit	It cannot properly read data in the nonvolatile	board or the outdoor
	Outdoor	7-time flash	and outdoor	It cannot properly read data in the nonvolatile	board or the outdoor
8	control		and outdoor	memory of the inverter P.C. board or the	electronic control P.C. board.
8	control		unit do not	memory of the inverter P.C. board or the	electronic control P.C. board.
	system		unit do not	outdoor electronic control P.C. board.	Refer to outdoor unit service
	system		operate.	outdoor electronic control P.C. board.	Refer to outdoor unit service
		2.5-second OFF	operate.		manual.
		2.5-second OFF			manual.
		Left lamp flashes.	Indoor unit		• Confirm the abnormality in
	Other	14-time flash	Indoor unit	An abnormality other than above mentioned is	• Confirm the abnormality in
9	Other		and outdoor	An abnormality other than above mentioned is	detail using the failure mode
9	abnormality		unit do not	detected.	recall function for outdoor
		2.5-second OFF	operate.		unit.
		2.5-second OFF

Mitsubishi Electronics MSY-A24NA, MSY-A15NA Troubleshooting check table, Indicates abnormalities

8-4. Troubleshooting check table

indicates abnormalities.

Not lighted

MSY-A15/17