Mitsubishi Electronics MSH-A18ND service manual Instruction of troubleshooting

8-2. Instruction of troubleshooting

Start

Indoor unit operates. Outdoor unit doesn't operate.

Indoor unit operates. Outdoor unit doesn't operate normally.

Indoor unit	OPERATION INDICATOR
doesn't receive
	lamp on the indoor unit is
the signal from
	flashing on and off.
remote controller.

Outdoor unit	Outdoor unit	Outdoor unit
operates when	doesn't	doesn't
the EMERGENCY	operate	stop even
OPERATION	when the	if indoor unit
switch is pressed.	EMERGENCY	stops.
	OPERATION
	switch is pressed.

Check room	Refer to	Refer to
temperature	"Check of	"Check of
thermistor.	outdoor unit".	outdoor unit".
Refer to 8-6.
"Test point
diagram and
voltage".

Unit doesn't	Indoor unit	Indoor unit
operate	operates when	doesn't operate
normal	the EMERGENCY	when the
operation in	OPERATION	EMERGENCY
COOL or	switch is pressed.	OPERATION
HEAT mode.		switch is pressed.

Refer to	Refer to 8-5.B	1.	Check indoor /
"Check of	"Check of		outdoor
R.V. coil".	remote controller		connecting wire.
	and receiver	2.	Refer to 8-5.C
	P.C. board".		"Check of indoor
			electronic control
			P.C. board".

Flash on and	2-time flash
off at 0.5-	Cause:
second	Indoor unit
intervals	• Trouble of
Cause:	room temp-
Indoor/	erature/
Outdoor unit	indoor coil
• Mis-wiring	thermistor

3-time flash Cause: Indoor unit

•Trouble of indoor fan motor

4-time flash Cause: Indoor unit

•Trouble of indoor unit control system

6-time flash	7-time flash
Cause:	Cause:
Outdoor unit	Outdoor unit
• Trouble of	• Trouble of
thermistor	outdoor
in outdoor	control
unit	system

Refer to 8-5. D "How to check mis-wiring (When outdoor unit doesn't work)".

Check room	Refer to
temperature	8-5. A
thermistor	"Check of
and indoor	indoor fan
coil thermis-	motor".
tor.
Refer to 8-6.
"Test point
diagram and
voltage".

Replace the indoor electronic control P.C. board.

Refer to	Replace the
"Check of	deicer
outdoor	P.C. board.
thermistor".

Refer to outdoor unit service manual.

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