York DHP30NWB21SDCP30NWB21SDHP36NWB21SDCP36NWB21S Service Manual page 55

6. Malfunction of Communication E6
Start
Cut off power supply. Check if
connection line of IDU and ODU
and the wire inside electric box
are correctly connected.
Correct connection?
Main board matches
with display board? Main board of
IDU matches with that of ODU?
yes
Communication cord is damaged?
Replace IDU's
main board
Malfunction eliminated?
Connect the line
no
according to
wiring diagram.
yes
no
yes
no
no
yes
End
Malfunction eliminated?
no
Match correctly
Malfunction eliminated?
according to product
specification
no
Replace
Malfunction eliminated?
communication
cord
no
Replace ODU's
main board.
.
yes
yes
yes
48