Mitsubishi Electronics MSZ-FD09NA service manual Troubleshooting Check Table, Lighted Blinking

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.

		L AREA R	POWER	Lighted
				Blinking
				Not lighted
No.	Abnormal	Operation indicator lamp		Symptom	Condition	Correspondence
	point
		POWER lamp flashes.
	Miswiring	0.5-second ON				• Refer to 9-6.	"How to check
					The serial signal from the outdoor unit is not
1	or serial					miswiring and serial signal er-
					received for 6 minutes.
	signal					ror".
		0.5-second OFF
	Indoor coil	POWER lamp flashes.
		2-time flash				• Refer to 9-7.the characteristics
	thermistor
2					The indoor coil or the room temperature	of indoor coil thermistor, and
	Room tem-				thermistor is short or open circuit.	the room temperature thermis-
	perature					tor.
	thermistor	2.5-second OFF
		POWER lamp flashes.
		3-time flash
3	Indoor fan				The rotational frequency feedback signal is	• Refer to 9-6.	"Check of in-
	motor				not emitted during the indoor fan operation.	door fan motor".
		2.5-second OFF
		POWER lamp flashes.
		4-time flash			It cannot properly read data in the nonvolatile
	Indoor con-					• Replace the indoor electronic
4					memory of the indoor electronic control P.C.
	trol system					control P.C. board.
					board.
		2.5-second OFF		Indoor unit and
		POWER lamp flashes.		outdoor unit do
				not operate.
		5-time flash			It consecutively occurs 3 times that the com-	• Refer to "How to check of in-
	Outdoor					verter/compressor".
					pressor stops for overcurrent protection or
5	power sys-					Refer to outdoor unit service
					start-up failure protection within 1 minute after
	tem					manual
					start-up.
						• Check the stop valve.
		2.5-second OFF
		POWER lamp flashes.
		6-time flash				• Refer to "Check of outdoor
6	Outdoor				The outdoor thermistors short or open circuit	thermistor".
	thermistors				during the compressor operation.	Refer to outdoor unit service
						manual.
			2.5-second OFF
		POWER lamp flashes.				• Replace the inverter P.C. board
	Outdoor	7-time flash			It cannot properly read data in the nonvolatile
7						or the outdoor electronic con-
	control sys-				memory of the inverter P.C. board or the out-	trol P.C. board.
	tem				door electronic control P.C. board.	Refer to outdoor unit service
			2.5-second OFF			manual.
		POWER lamp flashes.
		14-time flash				• Check the stop valve.
8	Other ab-				An abnormality other than above mentioned	• Confirm the abnormality in
	normality				is detected.	detail using the failure mode
						recall function for outdoor unit.
		2.5-second OFF
	Outdoor			Outdoor unit	It cannot properly read data in the nonvolatile	• Check the blinking pattern of
						the LED on the inverter P.C.
9	control sys- POWER lamp lights up			does not oper- memory of the inverter P.C. board or the out-
						board or the outdoor electronic
	tem			ate	door electronic control P.C. board.
						control P.C. board.

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