Mitsubishi Electronics MUZ-D30NA, MUZ-D36NA, MUY-D36NA, U1 Outdoor unit failure mode table

3. Outdoor unit failure mode table

MUZ-D30NA MUZ-D36NA MUY-D30NA MUY-D36NA

		LED indication
The left lamp of OPERA-	Abnormal point	(Outdoor P.C.					Indoor/outdoor
TION INDICATOR lamp		board)		Condition	Correspondence		unit failure mode
	(Failure mode / protection)
(Indoor unit)							recall function
		LED 1	LED 2
OFF	Non (Normal)	—	—	—	—		—
				IPM protection stop or lock protection stop is continuously	• Check the connection of the
					compressor connecting wire.
2-time flash	Outdoor power system	Lighting	Lighting	performed 3 times within 1 minute after the compres-	• Refer to 10-5.	"How to check	○
				sor gets started, or converter protection stop or bus-bar	inverter / compressor".
				voltage protection stop is continuously performed 3 times	• Refer to 10-5.	"Check of
				within 3 minutes after start-up.	compressor start failure".
					• Check the stop valve.
	Discharge temperature thermistor	Lighting	Once
	Defrost thermistor (MUZ)	Lighting	Once		• Refer to 10-5.	"Check of
	Ambient temperature thermistor	Lighting	Twice		outdoor thermistors".		○
3-time flash				Thermistor shorts or opens during compressor running.
	Fin temperature thermistor	Lighting	3 times
	P.C. board temperature thermistor	Lighting	4 times		• Replace the outdoor electronic
					control P.C. board.
	Outdoor heat exchanger tempera-	Lighting	9 times		• Refer to 10-5.	"Check of
	ture thermistor				outdoor thermistors".
					• Reconnect compressor con-
					nector.	"How to check
			Goes		• Refer to 10-5.
4-time flash	Overcurrent	Once		28 A current flow into intelligent power module.	inverter/ compressor."		—
			out
					• Refer to 10-5.	"Check of
					compressor start failure".
					• Check the stop valve.
				Temperature of discharge temperature thermistor exceeds	• Check refrigerant circuit and
5-time flash	Discharge temperature	Lighting	Lighting	241 °F (116 °C), compressor stops. Compressor can	refrigerant amount.		—
				restart if discharge temperature thermistor reads 212 °F	• Refer to 10-5.	"Check of
				(100 °C) or less 3 minutes later.	LEV".
6-time flash	High pressure	Lighting	Lighting	The outdoor heat exchanger temperature exceeds 158 °F	• Check refrigerant circuit and		—
				(70 °C) during cooling or the indoor gas pipe temperature	refrigerant amount.
				exceeds 158 °F (70 °C) during heating (MUZ).	• Check the stop valve.
	Fin temperature	3 times	Goes	The fin temperature exceeds 189 °F (87 °C) during opera-	• Check around outdoor unit.
			out	tion.	• Check outdoor unit air pas-
7-time flash					sage.		—
	P.C. board temperature	4 times	Goes	The P.C. board temperature exceeds 158 °F (70 °C) during	• Refer to 10-5.	"Check of
			out	operation.	outdoor fan motor".
8-time flash	Outdoor fan motor	Lighting	Lighting	Failure occurs continuously 3 times within 30 seconds	• Refer to 10-5.	"Check of	—
				after the fan gets started.	outdoor fan motor".
9-time flash	Nonvolatile memory data	Lighting	5 times	Nonvolatile memory data cannot be read properly.	• Replace the outdoor electronic		○
					control P.C. board.
				The frequency of the compressor is kept 80 Hz or more	• Check refrigerant circuit and
					refrigerant amount.
10-time flash	Discharge temperature	Lighting	Lighting	and the discharge temperature is kept under 102 °F (39 °C)			—
					• Refer to 10-5.	"Check of
				for more than 20 minutes.	LEV".
				Communication error occurs between the electronic control	• Check the connecting wire		—
	Communication error between			P.C. board and power board for more than 10 seconds.	between outdoor electronic
		Lighting	6 times		control P.C. board and power
	P.C. boards			The communication between boards protection stop is			○
					board.
				continuously performed twice.
				A short or open circuit is detected in the current sensor	• Replace the power board.		—
				during compressor operating.
	Current sensor	Lighting	7 times
11-time flash				Current sensor protection stop is continuously performed			○
				twice.
				Zero cross signal cannot be detected while the compres-	• Check the connecting wire		—
				sor is operating.	among electronic control P.C.
	Zero cross detecting circuit	5 times	Goes out		board, noise filter P.C. board
				The protection stop of the zero cross detecting circuit is	and power board.		○
				continuously performed 10 times.

NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (10-3.).

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