Mitsubishi Electric MXZ-A14WV Service Manual page 59

Outdoor unit does not operate. (LED display: Both LED1 and LED2 lighting)
B B Check of outdoor unit serial signal
Start
1. Check the indoor unit with referring to "How to check mis-wiring and serial signal error" in service manual of indoor unit.
2. Turn off the power supply of the indoor and outdoor unit and connect the indoor/ outdoor unit connecting wire correctly.
3. Check the connection of indoor/ outdoor unit connecting wire in the outdoor unit terminal block, and check the connection
of the connector CN601: unit A, CN602: unit B (MXZ-A14/A18WV)/ CN601: unitA, CN602: unitB, CN603: unitC, CN604:
unitD (MXZ-A26/A32WV) in the outdoor electronic control P.C. board.
4. Disconnect the lead wire to the compressor. 3 minutes after turning on the power supply, start EMERGENCY
OPERATION.
Is there voltage from 5V DC to 10V DC between
No. 3 (+) and N (-) in the outdoor terminal block?
Yes
Recheck a connected circumstance of the indoor/ outdoor unit connecting wire.
No
Replace the outdoor electronic control P.C. board.
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