MITSUBISHI ELECTRIC MXZ-24UV - Manual (Page 29)

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C C Check of R. V. coil
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Start
1. Disconnect the lead wire leading to the compressor.
2. Turn on power supply to the indoor and outdoor unit, three minutes later
EMERGENCY OPERATION (HEAT operation) starts.
Is there voltage of 230V AC between pin1 and
pin 2 at connector CN913?
Turn off power supply of indoor and outdoor unit.
1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector (CN851, CN852) in the electronic
control P. C. board.
2. Turn on power supply to the indoor and outdoor unit, three
minutes later EMERGENCY OPERATION
(HEAT operation) starts.
Replace the 4-way valve
Replace the noise filter P. C. board.
Replace the R. V. coil
Is there voltage 12V DC between
the connector CN852 pin 1 (+)
and pin 5 (-)?
Replace the electronic
control P. C. board.
Disconnect the connector
CN913 in noise filter P. C.
board, and measure the
resistance of R. V. coil to
check the integrity.
Start
1. Disconnect the lead wire leading to the compressor.
2. Turn on power supply to the indoor and outdoor unit, three minutes later
EMERGENCY OPERATION (COOL operation) starts.
Is there voltage of 230V AC between pin1 and
pin 2 at connector CN913?
1. Turn off power supply of indoor and outdoor unit, and
disconnect the connector (CN851, CN852) in the electronic
control P. C. board.
2. Turn on power supply to the indoor and outdoor unit, three
minutes later EMERGENCY OPERATION
(COOL operation) starts.
Replace the 4-way valve
Replace the noise filter P. C. board.
Is there voltage 12V DC between
the connector CN852 pin 1 (+)
and CN851 pin 5 (-)?
W 1
Replace the electronic control P. C. board.
W 1 If the connector CN913 is not connected or R. V. coil is open, voltage
occurs between terminals even when the control is OFF.
• When heating operation does not work.
• When cooling operation does not work.
The cooling operation or heating operation does not operate. (LED display: 0 00 0 )
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