Mitsubishi Electric PUHZ-SW75VAA-SC Service Manual page 28

Abnormal point and detection method
Check code
Compressor overcurrent interruption
Abnormal if overcurrent DC bus or
compressor is detected after compressor
starts operating for 30 seconds.
UP
(4210)
Remote controller transmission error (E0)/
signal receiving error (E4)
1 Abnormal if main remote controller
cannot receive normally any transmission
from indoor unit of refrigerant address "0"
for 3 minutes.
(Check code: E0)
1 Abnormal if indoor controller board
cannot receive normally any data from
remote controller board or from other
E0
indoor controller board for 3 minutes.
or
(Check code: E4)
E4
2 Indoor controller board cannot receive
(6831
or
any signal from remote controller for 2
6834)
minutes. (Check code: E4)
Remote controller control board
1 Abnormal if data cannot be normally
E1
read from the nonvolatile memory of the
or
remote controller control board.
E2
(Check code: E1)
(6201
or
2 Abnormal if the clock function of remote
6202)
controller cannot be normally operated.
(Check code: E2)
OCH651A
Cause
1 Stop valve of outdoor unit is
closed.
2 Decrease of power supply
voltage
3 Looseness, disconnection or
converse of compressor wiring
connection
4 Defective fan of indoor/outdoor
units
5 Short cycle of indoor/outdoor
units
6 Defective input circuit of
outdoor controller board
7 Defective compressor
8 Defective outdoor power circuit
board
9 DIP switch setting difference of
outdoor controller circuit board
1 Contact failure at transmission
wire of remote controller
2 Miswiring of remote controller
3 Defective transmitting receiving
circuit of remote controller
4 Defective transmitting receiving
circuit of indoor controller board
of refrigerant address "0"
5 Noise has entered into the
transmission wire of remote
controller.
1 Defective remote controller
28
Judgment and action
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U·V·W phase) to
compressor. Refer to "9-6.TEST POINT
DIAGRAM" (Outdoor power circuit board).
4 Check indoor/outdoor fan.
5 Solve short cycle.
6 Replace outdoor controller circuit board.
Note: Before the replacement of the outdoor
controller circuit board, disconnect the
wiring to compressor from the outdoor
power circuit board and check the output
voltage among phases, U, V, W, during
test run.
No defect on board if voltage among
phases (U-V, V-W and W-U) is same.
Make sure to perform the voltage check
with same performing frequency.
7 Check compressor. Refer to "9-4. HOW TO
CHECK THE PARTS".
8 Replace outdoor power circuit board.
9 Check the DIP switch setting of outdoor
controller circuit board.
1 Check disconnection or looseness of indoor
unit or transmission wire of remote controller.
2 Check wiring of remote controller.
• Total wiring length: Max. 500 m
(Do not use cable o 3 or more.)
• The number of connecting indoor units:
Max. 6 units
• The number of connecting remote
controller: Max. 1 unit
If the cause of trouble is not in above 1–3,
3 Diagnose remote controller (PAC-IF011B-E only).
a) When "RC OK" is displayed,
Remote controllers have no problem.
Turn the power off, and on again to check.
If abnormality generates again, replace
indoor controller board.
b) When "RC NG" is displayed,
Replace remote controller.
c) When "RCE3" or "ERC00-66" is displayed,
noise may be causing abnormality.
Note: If the unit is not normal after replac-
ing indoor controller board in group
control, indoor controller board of
address "0" may be abnormal. For
the controllers other than PAC-
IF011B-E, refer to Installation
Manual or Service Handbook of
the indoor unit.
1 Replace remote controller.