Indoor/Outdoor Unit Communication Error; Non Defined Error Code; Serial Communication Error - Mitsubishi Electric PUHZ-SW40VHA Service Manual

Error Code Abnormal points and detection method
Indoor/outdoor unit communication
error (Signal receiving error)
1 Abnormal if indoor controller board could
not receive any signal normally for 6
minutes after turning the power on.
2 Abnormal if indoor controller board could
not receive any signal normally for 3
minutes.
3 Consider the unit as abnormal under
the following condition. When 2 or more
indoor units are connected to an outdoor
unit, indoor controller board could not
E6
receive a signal for 3 minutes from
outdoor controller circuit board, a signal
which allows outdoor controller circuit
board to transmit signals.
Indoor/outdoor unit communication
error (Signal receiving error)
(Outdoor unit)
Abnormal if outdoor controller circuit board
E8
could not receive anything normally for 3
minutes.
Indoor/outdoor unit communication
error (Transmitting error) (Outdoor unit)
1 Abnormal if "0" receiving is detected
30 times continuously though outdoor
E9
controller circuit board has transmitted
"1".
2 Abnormal if outdoor controller circuit
board could not find blank of transmission
path for 3 minutes.

Non defined error code

This code is displayed when non defined
error code is received.
EF

Serial communication error

1 Abnormal if serial communication
between outdoor controller circuit board
and outdoor power circuit board is
defective.
Ed
OCH525
Case
1 Contact failure, short circuit or
miswiring (converse wiring) of
indoor/outdoor unit connecting
wire
2 Defective transmitting receiving
circuit of outdoor controller
circuit board.
3 Defective transmitting receiving
circuit of indoor controller
board.
4 Noise has entered into indoor/
outdoor unit connecting wire.
5 Defective fan motor
6 Defective rush current resistor
of outdoor power circuit board
1 Contact failure of indoor/
outdoor unit connecting wire
2 Defective communication circuit
of outdoor controller circuit board
3 Defective communication circuit
of indoor controller board
4 Noise has entered into indoor/
outdoor unit connecting wire.
1 Indoor/ outdoor unit connecting
wire has contact failure.
2 Defective communication circuit
of outdoor controller circuit board
3 Noise has entered power supply.
4 Noise has entered indoor/
outdoor unit connecting wire.
1 Noise has entered transmission
wire of remote controller.
2 Noise has entered indoor/
outdoor unit connecting wire.
3 Outdoor unit is not a series of
power-inverter.
4 Model name of remote
controller is PAR-S25A.
1 Breaking of wire or contact
failure of connector CN2
between the outdoor controller
circuit board and the outdoor
power circuit board
2 Breaking of wire or contact
failure of connector CN4
between the outdoor controller
circuit board and the outdoor
power circuit board
3 Defective communication circuit
of outdoor power circuit board
4 Defective communication circuit
of outdoor controller circuit board
for outdoor power circuit board
22
Judgment and action
w 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.
1 Check disconnecting or looseness of indoor
/outdoor unit connecting wire of indoor unit
or outdoor unit.
Check all the units in case of twin/triple/
quadruple indoor unit system.
2~4 Turn the power off, and on again to check.
If abnormality generates again, replace
indoor controller board or outdoor controller
circuit board.
w Other indoor controller board may have
defect in case of twin/triple/quadruple indoor
unit system.
5 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.
6 Check the rush current resistor on outdoor
power circuit board with tester. If open is
detected, replace the power circuit board.
1 Check disconnection or looseness of indoor/
outdoor unit connecting wire of indoor or
outdoor units.
2~4 Turn the power off, and on again to
check. Replace indoor controller board
or outdoor controller circuit board if
abnormality is displayed again.
1 Check disconnection or looseness of indoor/
outdoor unit connecting wire.
2~4 Turn the power off, and on again to
check. Replace outdoor controller circuit
board if abnormality is displayed again.
12 Turn the power off, and on again to check.
Replace indoor controller board or outdoor
controller circuit board if abnormality is
displayed again.
3 Replace outdoor unit with power-inverter type
outdoor unit.
4 Replace remote controller with MA remote
controller.
12 Check connection of each connector CN2
and CN4 between the outdoor controller
circuit board and the outdoor power circuit
board.
3 Replace outdoor power circuit board.
4 Replace outdoor controller circuit board.