Operating Instructions and Installation
Samsung Electronics
4-15
4-3-4 Communication error after completion of tracking
Indoor unit display
(Operation)
Defrost)
(Reservation) X(Fan) X(MPI)
Criteria
If communication between indoor and outdoor units has been blocked for 2 minutes during operation
Cause of problem
Communication error between indoor and outdoor unit
No
Yes
Replace PCB of
indoor unit after checking out the communica-
tion line
At this time, the voltage between
lines is a square wave that is above DC±0.7V as
shown in the picture below
+0.7V
-0.7V
After removing the communication line
that links outdoor to indoor units measure
2 lines of the outdoor unit with scope.
After reconnecting the communication
line that links outdoor and indoor units,
remove communication connector in the
indoor PCB. If communication does not
work during operation, replace PCB of
the indoor unit.
Replace PCB after checking the
communication line of the outdoor unit
PCB and connector
Good
defect
Troubleshooting
