Communication Malfunction Of Some Indoor Units - York DHM42CMB21S Service Manual

(7) Communication malfunction
Main checking points:
If the connection wire between the indoor unit and outdoor unit is connected well, if the wires inside the unit are connected well
I f the indoor mainboard or outdoor main board is broken
Flow chart:
Communication malfunction of some
indoor units
De-energize,check the connection
wire of indoor and outdoor unit and
the wire of the eletric box is
connected correctly
Connected correctly
yes
De-energize, change the communication wire of the well-
communicated indoor unit and malfunction indoor unit,
then energize the unit and wait for 3 min
The malfunction indoor unit
resumes normal
no
Replace the mainboard of the
malfunction indoor unit
End
Reconnect according to
no
the wiring diagram
yes
Replace outdoor
mainboard
yes
Eliminate the malfunction
no
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