Mitsubishi Electronics MSZ-FD25VAS, MSZ-FD35VAS service manual Troubleshooting Check Table

10-4. 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 CLEAN PLASMA	Lighted
		Blinking
		Not lighted

No.	Abnormal	Operation indicator lamp
	point
		POWER lamp flashes.

Symptom Condition Correspondence

	Miswiring	0.5-second ON
1	or serial
	signal
		0.5-second OFF
	Indoor coil	POWER lamp flashes.
2	thermistor	2-time flash
	Room
	temperature
	thermistor	2.5-second OFF
		POWER lamp flashes.
		3-time flash
3	Indoor fan
	motor
		2.5-second OFF
	Indoor	POWER lamp flashes.
		4-time flash
4	control
	system
		2.5-second OFF
		POWER lamp flashes.
5	Outdoor	5-time flash
	power

system

2.5-second OFF

POWER lamp flashes. 6-time flash

Outdoor

6 thermistors

2.5-second OFF

	Outdoor	POWER lamp flashes.
		7-time flash
	control
7
	system

2.5-second OFF

POWER lamp flashes.

14-time flash

Other

8 abnormality

2.5-second OFF

Outdoor

9 control POWER lamp lights up. system

Indoor unit and outdoor unit do not operate.

Outdoor unit does not operate.

The serial signal from the outdoor unit is not received for 6 minutes.

The indoor coil or the room temperature thermistor is short or open circuit.

The rotational frequency feedback signal is not emitted during the indoor fan operation.

It cannot properly read data in the nonvolatile memory of the indoor electronic control P.C. board.

It consecutively occurs 3 times that the compressor stops for overcurrent protection or start-up failure protection within 1 minute after start-up.

The outdoor thermistors short or open circuit during the compressor operation.

It cannot properly read data in the nonvolatile memory of the inverter P.C. board or the outdoor electronic control P.C. board.

An abnormality other than above mentioned is detected.

It cannot properly read data in the nonvolatile memory of the inverter P.C. board or the outdoor electronic control P.C. board.

•Refer to 10-6.D"How to check miswiring and serial signal error".

•Refer to 10-7.the characteristics of indoor coil thermistor, and the room temperature thermistor.

•Refer to 10-6.A"Check of indoor fan motor".

•Replace the indoor electronic control P.C. board.

•Refer to "How to check of inverter/compressor".

Refer to outdoor unit service manual.

•Check the stop valve.

•Refer to "Check of outdoor thermistor".

Refer to outdoor unit service manual.

•Replace the inverter P.C. board or the outdoor electronic control P.C. board. Refer to outdoor unit service manual.

•Check the stop valve.

•Confirm the abnormality in detail using the failure mode recall function for outdoor unit.

•Check the blinking pattern of the LED on the inverter P.C. board or the outdoor electronic

control P.C. board.

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