Serial communication error
Mitsubishi Electric · PUZ-HA30/36NHA4 Outdoor Unit
What does Ed (00) mean?
This error indicates a failure in serial communication. It can occur between the outdoor controller circuit board and the outdoor power circuit board, or between the outdoor controller circuit board and the M-NET board. Causes include broken wires, contact failures in connectors (CN, CNMNT, CND), defective communication circuits on the boards, or noise interference on the M-NET transmission wire.
Common Causes
- Serial communication failure between main control board and peripheral devices.
- Incorrect serial communication protocol setting (e.g., Baud rate, parity).
- Damaged communication wiring.
- Faulty communication interface on one of the devices.
- Interference on communication lines.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Check the connection of connectors CN and CN between the outdoor controller circuit board and the outdoor power circuit board for disconnections or contact failures.
- 2
Check the connection wire between the outdoor controller circuit board (CNMNT) and the M-NET board (CN and CND) for disconnection, looseness, or breaking.
- 3
Review the M-NET transmission wiring method for proper installation.
- 4
If communication between the outdoor controller and outdoor power board fails, replace the outdoor power circuit board.
- 5
If communication between the outdoor controller and outdoor power board fails, replace the outdoor controller circuit board.