Mitsubishi Electronics MUZ-FD12NA- U1, MUZ-FD09NA- U1 Outdoor unit failure mode table

3. Outdoor unit failure mode table

POWER lamp	Abnormal point	LED indication
(Indoor unit)	(Failure mode / protection)	(Outdoor P.C. board)

Condition

Correspondence

Indoor/

outdoor unit failure mode recall function

Outdoor unit failure mode recall function

OFF	None (Normal)	—	—	—		—	—
2-time flash	Outdoor power system		Overcurrent protection stop is	•Reconnect connectors.
2.5 seconds			continuously performed 3 times within	•Refer to 10-5.	"How	○	○
OFF		—	1 minute after the compressor gets	to check inverter/
			started.	compressor".
				•Check stop valve.
3-time flash	Discharge temperature	1-time flash every	Thermistor shorts or opens during	•Refer to 10-5.	"Check
2.5 seconds	thermistor	2.5 seconds	compressor running.	of outdoor thermistors".
OFF				Defective outdoor
	Defrost thermistor
				thermistors can be
				identified by checking
	Fin temperature thermistor	3-time flash				○	○
				the blinking pattern of
		2.5 seconds OFF
				LED.
	P.C. board temperature	4-time flash
	thermistor	2.5 seconds OFF
	Ambient temperature	2-time flash
	thermistor	2.5 seconds OFF
4-time flash	Overcurrent	11-time flash	Large current flows into intelligent	•Reconnect compressor
2.5 seconds		2.5 seconds OFF	power module.	connector.	"How		○
OFF				•Refer to 10-5.		—
				to check inverter/
				compressor".
				•Check stop valve.
	Compressor synchronous	12-time flash	Waveform of compressor current is	•Reconnect compressor
	abnormality (Compressor start-	2.5 seconds OFF	distorted.	connector.	"How		○
	up failure protection)			•Refer to 10-5.		—
				to check inverter/
				compressor".
5-time flash	Discharge temperature		Temperature of discharge temperature	•Check refrigerant circuit
2.5 seconds			thermistor exceeds 241°F (116°C),	and refrigerant amount.
OFF			compressor stops.	•Refer to 10-5.	"Check		○
		—	Compressor can restart if discharge	of LEV".		—
			temperature thermistor reads 212°F
			(100°C) or less 3 minutes later.
6-time flash	High pressure		Temperature of indoor coil thermistor	•Check refrigerant circuit
2.5 seconds		—	exceeds 158°F (70°C) in HEAT mode.	and refrigerant amount.		—	○
OFF			Temperature of defrost thermistor	•Check stop valve.
			exceeds 158°F (70°C) in COOL mode.
7-time flash	Fin temperature/ P.C. board	7-time flash	Temperature of fin temperature	•Check around outdoor
2.5 seconds	temperature	2.5 seconds OFF	thermistor on the inverter P.C. board	unit.
OFF			exceeds 167 ~ 176°F (75 ~ 80°C), or	•Check outdoor unit air		—	○
			temperature of P.C. board temperature	passage.	"Check
			thermistor on the inverter P.C. board	•Refer to 10-5.
			exceeds 158 ~ 167°F (70 ~ 75°C).	of outdoor fan motor".
8-time flash	Outdoor fan motor		Outdoor fan has stopped 3 times in a	•Refer to 10-5.	"Check		○
2.5 seconds		—	row within 30 seconds after outdoor fan	of outdoor fan motor".		—
OFF			start-up.	Refer to 10-5.	"Check
				of inverter P.C. board".
9-time flash	Nonvolatile memory data	5-time flash	Nonvolatile memory data cannot be	•Replace the inverter		○	○
OFF		2.5 seconds OFF	read properly.	P.C. board.
2.5 seconds
10-time flash	Discharge temperature		Temperature of discharge temperature	•Refer to 10-5.	"Check
2.5 seconds		—	thermistor has been 122°F (50°C) or	of LEV".		—	○
OFF			less for 20 minutes.	•Check refrigerant circuit
				and refrigerant amount.
11-time flash	DC voltage	8-time flash	DC voltage of inverter cannot be	•Refer to 10-5.	"How
2.5 seconds		2.5 seconds OFF	detected normally.	to check inverter/			○
OFF				compressor".		—
	Each phase current of	9-time flash	Each phase current of compressor
	compressor	2.5 seconds OFF	cannot be detected normally.
12-time flash	Overcurrent Compressor open-	10-time flash	Large current flows into intelligent	•Reconnect compressor
2.5 seconds	phase	2.5 seconds OFF	power module (IPM).	connector.	"How
OFF			The open-phase operation of	•Refer to 10-5.
			compressor is detected.	to check inverter/		—	○
			The interphase short out occurs in the	compressor".
			output of the intelligent power module
			(IPM).
			The compressor winding shorts out.
14-time flash	Stop valve (Closed valve)	14-time flash	Closed valve is detected by compressor	•Check stop valve		○	○
OFF		2.5 seconds OFF	current.
2.5 seconds

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

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