Check Of R. V. Coil - Mitsubishi Electric MSH09TW Service Manual

The cooling operation or heating operation does not operate. (LED display: 0 0 0 0 )
K K Check of R. V. coil
• When heating operation does not work.
Start
1. Disconnect the lead wire leading to the compressor.
2. 3 minutes after turning on the power suppy, start EMERGENCY
OPERATION in HEAT mode.
Is there voltage of 208V AC - 230V AC between
pin1 and pin 2 at connector CN913?
Yes
Turn off power supply of indoor and outdoor unit.
Disconnect the connector
CN913 in noise filter P. C.
board, and measure the
resistance of R. V. coil to
check the integrity.
Yes
Replace the 4-way valve.
• When cooling operation does not work.
Start
1. Disconnect the lead wire leading to the compressor.
2. 3 minutes after turning on the power suppy, start EMERGENCY
OPERATION in COOL mode.
Is there voltage of 208V AC - 230V AC between
pin1 and pin 2 at connector CN913? W1
Yes
1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector (CN851, CN852) in the electronic
control P. C. board.
2. 3 minutes after turning on the power suppy, start
EMERGENCY OPERATION in COOL mode.
Is there voltage 12V DC between
the connector CN852 pin 1 (+)
and CN851 pin 5 (-)?
Yes
Replace the electronic control P. C. board.
(MXZ30TN MXZ30TN2)
No
No
Replace the R. V. coil.
No
No
Replace the noise filter P. C. board.
1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector (CN851, CN852) in the electronic
control P. C. board.
2. 3 minutes after turning on the power suppy, start
EMERGENCY OPERATION in HEAT mode.
Is there voltage 12V DC between
the connector CN852 pin 1 (+)
and CN851 pin 5 (-)?
Yes
Replace the noise filter P. C. board.
Replace the 4-way valve.
W1 If the connector CN913 is not connected or R. V. coil is open,
occurs between terminals even when the control is OFF.
90
No
Replace the electronic
control P. C. board.