Vermont Casting MSY-D30NA, MSZ-D36NA, MSZ-D30NA, MSY-D36NA service manual Troubleshooting Check Table

9-4. 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.

OPERATION INDICATOR

Lighted

Blinking

Not lighted

No.	Abnormal	Operation indicator lamp	Symptom	Condition	Correspondence
	point
		Left lamp flashes.	Indoor unit
		0.5-second ON
1	Miswiring or		and outdoor	The serial signal from the outdoor unit is not	• Refer to 9-6. "How to check miswiring
	serial signal		unit do not	received for a maximum of 6 minutes.	and serial signal error".
		0.5-second OFF	operate.
		Left lamp flashes.
	Indoor coil	2-time flash
	thermistor		Indoor unit		• Refer to 9-7.the characteristics of indoor
			and outdoor	The indoor coil or the room temperature
2					coil thermistor, and the room tempera-
			unit do not	thermistor is short or open circuit.
		2.5-second OFF			ture thermistor.
	Room		operate.
	temperature
	thermistor
		Left lamp flashes.	Indoor unit
	Indoor fan	3-time flash		The rotational frequency feedback signal is not • Refer to 9-6. "Check of indoor fan mo-
3			and outdoor
	motor		unit do not	emitted during the indoor fan operation.	tor".
		2.5-second OFF	operate.
		Left lamp flashes.	Indoor unit
	Indoor con-	4-time flash		It cannot properly read data in the nonvolatile	• Replace the indoor electronic control
4			and outdoor
	trol system		unit do not	memory of the indoor electronic control P.C.	P.C. board.
		2.5-second OFF	operate.	board.
		Left lamp flashes.
	Outdoor	5-time flash	Indoor unit	It consecutively occurs 3 times that the	• Refer to "How to check of inverter/
			and outdoor	compressor stops for overcurrent protection or	compressor".
5	power sys-
			unit do not	start-up failure protection within 1 minute after	Refer to outdoor unit service manual.
	tem
			operate.	start-up.	• Check the stop valve.
		2.5-second OFF
		Left lamp flashes.	Indoor unit
	Outdoor	6-time flash		The outdoor thermistors short or open circuit	• Refer to "Check of outdoor thermistor".
6			and outdoor
	thermistors		unit do not	during the compressor operation.	Refer to outdoor unit service manual.
		2.5-second OFF	operate.
		Left lamp flashes.	Indoor unit
7	Outdoor con-	7-time flash		It cannot properly read data in the nonvola-	• Replace the inverter P.C. board or the
			and outdoor	tile memory of the inverter P.C. board or the	outdoor electronic control P.C. board.
	trol system		unit do not	outdoor electronic control P.C. board.	Refer to outdoor unit service manual.
			operate.
		2.5-second OFF
		Left lamp flashes.
		14-time flash	Indoor unit		• Confirm the abnormality in detail using
	Other abnor-			An abnormality other than above mentioned is
8			and outdoor
	mality		unit do not	detected.	the failure mode recall function for
		2.5-second OFF	operate.		outdoor unit.

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