Midea PTAC Series Service Manual page 28

10.2.2 Communication malfunction between main control board and display board. (
Error Code
Malfunction decision
conditions
Supposed causes
Troubleshooting:
E4
Main control board does not receive feedback from display board
during 120 seconds.
Wiring mistake
●
Faulty
●
Faulty
●
Communication malfunction between main
control board and display board
Check the signal wire between the
Display board and the main board,
is it connected good?
No
Yes
Reconnect and retry. Is error
still display?
Yes
Replace display board, Is error
still display?
Yes
Replace the main control
board
display board
main control board
E4
)
No
No
Trouble is solved
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