Mitsubishi Electric PUZ-SWM60VAA Service Manual page 31

Check code Abnormal point and detection method
Indoor/outdoor unit communication
error (Signal receiving error)
Abnormal if indoor controller board
could not receive any signal normally
for 6 minutes after turning the power on.
Abnormal if indoor controller board
could not receive any signal normally
for 3 minutes.
Consider the unit as abnormal under
the following condition. When 2 or more
indoor units are connected to an out-
door unit, indoor controller board could
E6
not receive a signal for 3 minutes from
(6840)
outdoor controller circuit board, a signal
which allows outdoor controller circuit
board to transmit signals.
Indoor/outdoor unit communication
error (Transmitting error)
Abnormal if "1" receiving is detected 30
times continuously though indoor controller
E7
board has transmitted "0".
OCH809A
Cause
Contact failure, short circuit or
miswiring (reversed wiring)of
indoor/outdoor unit connecting
wire.
Defective transmitting receiving
circuit of outdoor controller circuit
board.
Defective transmitting receiving
circuit of indoor controller circuit
board.
Noise has entered into indoor/
outdoor unit connecting wire.
High pressure(High pressure
switch 63H operated) or High
compressor temperature
(Thermal protector TRS
operated)
Defective fan motor
Defective rush current resistor
of outdoor power circuit board
Defective transmitting receiving
circuit of indoor controller board
Noise has entered into power
supply
Noise has entered into outdoor
control wire
31
Judgment and action
Check LED display on outdoor controller circuit
board. (Connect A-Control service tool (PAC-
SK52ST))
Refer to EA-EC item if LED displays EA-AC.
Check disconnecting or looseness of indoor/
outdoor unit connecting wire of indoor unit or
outdoor unit.
Check all the units in the case of twin/triple/
quadruple indoor unit.
– Turn the power off, wait 10 minutes and
on again to check.
If abnormality occurs again, replace indoor
controller board or outdoor controller circuit
board.
Note: Other indoor controller board may have
defect in the case of twin/triple/quadruple
indoor unit system.
Turn the power off, and detach fan motor from
connector (CNF1, 2). Then turn the power on
again.
If abnormality is not displayed, replace fan
motor.
If abnormality is displayed, replace outdoor
controller circuit board.
Check the rush current resistor on outdoor
power circuit board with tester.
If open is detected, replace the power circuit
board.
– Turn the power off, and on again to check.
If abnormality occurs again, replace
indoor controller board.