Mitsubishi Electric Mr. SLIM MSZ-FA25VA Technical Manual página 284

Resolución de averías
Check of R.V. coil
H
First of all, measure the resistance of R.V. coil to check if the coil is defective. Refer to 11-4.
In case CN721 is not connected or R.V. coil is open, voltage is generated between the
terminal pins of the connector although any signal is not being transmitted to R.V. coil.
Check if CN721 is connected.
Unit operates COOL mode even if it is set to HEAT mode.
Disconnect connector (CN61) between
the compressor and intelligent power
module.
Turn ON the power supply and press
EMERGENCY OPERATION switch
twice (HEAT mode).
Unit operates HEAT mode even if it is set to COOL mode.
Disconnect connector (CN61) between
the compressor and the intelligent power
module.
Turn ON the power supply and press
EMERGENCY OPERATION switch once
(COOL mode).
Outdoor fan motor does not operate.
Check of outdoor fan motor
I
Check the resistance of fan motor. (Refer to 11-4.)
Disconnect the connector CN771 on the inverter
P.C. board.
Disconnect the connector (CN61) between
compressor and power transistor module.
Turn ON the power supply and press the
EMERGENCY OPERATION switch.
284
Is there 230V AC between CN7211 and
2 on the inverter P.C.board 3 minutes
after the power supply is turned ON?
Is there 230V AC between CN7211 and
2 on the inverter P.C. board 3 minutes
after the power supply is turned ON?
No
Is the resistance of fan
motor normal?
Yes
Does the upper lamp of
OPERATION INDICATOR
lamp on the indoor unit
light up?
Yes
Replace the 4-way valve.
No
Replace the 4-way valve.
Replace the outdoor
fan motor.
3 minutes after, is there
voltage 230V AC
between CN771 2 and
3 on the inverter P.C.
board?
Yes
Replace the
outdoor fan motor.
No
Replace the
inverter P.C. board.
Inverter P.C. board
(Soldered side)
CN721
Yes Replace the
inverter P.C. board.
No
Replace the
inverter P.C. board.