Mitsubishi Heavy Industries SRC25QA-S Technical Manual Download

Page: 39 / 102

-36-

(5) Indication of self-diagnosis

When the air conditioner stops abnormally, the cause is indicated with lamps. Three minutes
after abnormal stop, use the remote controller to start the appliance. The error indication will
disappear and the appliance will commence operation

(2)

Indoor indication

Content of failure

Main cause

Indication (flash, light up) conditions

RUN lamp

TIMER

lamp

Light up

Flash 6
times

Error of
communication
between indoor and
outdoor units

Connection wire break, poor
contacting, defective indoor and
outdoor circuit boards, defective
power supply

Indoor circuit board ←→outdoor circuit
board: signal over 10 sec. (with power),
even over 1 min. and 50 sec. (operating),
no signal (compressor stops)

Flash 1
time

Light up

Error of indoor heat
exchanger sensor

Wire break of indoor heat
exchanger sensor, poor plug
contacting

The operation stops and the wire break of
the heat exchanger sensor is detected (wire
break is determined when it is detected
within 15 sec. at a temperature of
below-20

℃

) (No indication during

operation)

Flash 2
times

Light up

Room temperature
sensor error

Room temperature sensor wire
break, poor joint contacting

The operation stops and the wire break of
the heat exchanger sensor is detected (wire
break is determined when it is detected
within 15 sec. at a temperature of
below-20

℃

) (No indication during

operation)

Flash 5
times

Light up

Voltage error

Voltage is abnormal.

Flash 6
times

Light up

Indoor fan motor error

Defective fan motor, poor plug
contacting, defective indoor
circuit board

When the air conditioner is operating and
the indoor fan motor is ON, the rotational
frequency of the indoor fan motor is 300
rpm for over 30sec. (The air conditioner
stops.)

Light up

Flash 3
times

Over current (safe
current)

Operating with overload, over
current

Light up

Flash 4
times

Power transistor failure

Failure of power transistor

Light up

Flash 5
times

Compressor over heat

Insufficient refrigerant
Defective vent-pipe sensor
Disconnecting valve closed

When the value of vent-pipe sensor
exceeds the setting (The air conditioner
stops.)

Continuous
flashing

Flash 2
times

Outdoor heat
exchanger liquid pipe
sensor error

Wire break of outdoor heat
exchanger liquid pipe sensor
Poor joint connection

The operation stops and the wire break of
the outdoor heat exchanger sensor is
detected (wire break is determined when it
is detected within 15 sec. at a temperature
of below-50

℃

)

(No indication during operation)

Continuous
flashing

Flash 1
time

Outdoor air temp.
sensor error

Wire break of external
temperature sensor, poor joint
contacting

The operation stops and the wire break of
the outdoor heat exchanger sensor is
detected (wire break is determined when it
is detected within 15 sec. at a temperature
of below-40

℃

)

(No indication during operation)

Continuous
flashing

Flash 4
times

Vent-pipe sensor error

Wire break of vent-pipe sensor,
poor joint contacting

After the rotational frequency of over 0 rps
of outdoor unit lasts for 9 minutes; the
temperature measured by the vent-pipe
sensor of compressor is <7

℃

for more

than 15 sec. (The air conditioner stops.)

Light up

Flash 1
time

Power cut

Lock of compressor, output
missing phase of compressor,
short circuit of wiring of
compressor
Defective outdoor circuit board
Defective EEV
Disconnecting valve closed

When the compressor is started and the
output current of the inverter (current of
compressor motor) exceeds the setting
(The air conditioner stops.)

Light up

Flash 2
times

Outdoor unit error

Damage of mains transformer,
wiring break of compressor, wire
break of vent-pipe sensor, poor
joint contacting, disconnecting
valve closed, insufficient
refrigerant, defective EEV

The outdoor unit stops due to abnormal
cause or the input current is lower than the
setting for 3 min.

(The air conditioner stops.)

Flash 2
times

Rotor lock

Defective compressor, output
missing phase of compressor,
wiring break of compressor,
defective circuit board of outdoor
unit

The position of magnetic pole of the
compressor motor can’t be correctly
detected when the compressor is started.

(The air conditioner stops.)

Note: (1) It can’t be started with the remote controller 3 minutes after abnormal stop. The abnormal stop disappears when the power of the

air conditioner is switched off.