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Check code Abnormal point and detection method
Compressor overcurrent interruption
Abnormal if overcurrent DC bus or
compressor is detected after compressor
starts operating for 30 seconds.
UP
Remote controller transmission error
(E0)/signal receiving error (E4)
1 Abnormal if main or sub remote
controller cannot receive normally
any transmission from indoor unit of
refrigerant address "0" for 3 minutes.
(Check code : E0)
2 Abnormal if sub remote controller could
not receive any signal for 2 minutes.
(Check code: E0)
E0
or
1 Abnormal if indoor controller board
E4
cannot receive normally any data from
remote controller board or from other
indoor controller board for 3 minutes.
(Check code: E4)
2 Indoor controller board cannot receive
any signal from remote controller for 2
minutes. (Check code: E4)
Remote controller control board
1 Abnormal if data cannot be normally
read from the nonvolatile memory of the
E1
remote controller control board.
(Check code: E1)
or
2 Abnormal if the clock function of remote
E2
controller cannot be normally operated.
(Check code: E2)
Remote controller transmission error
(E3)/signal receiving error (E5)
1 Abnormal if remote controller could not
find blank of transmission path for 6
seconds and could not transmit.
(Check code: E3)
2 Remote controller receives transmitted
data at the same time, compares the
data, and when detecting it, judges
E3
different data to be abnormal 30
or
continuous times. (Check code: E3)
E5
1 Abnormal if indoor controller board could
not find blank of transmission path.
(Check code: E5)
2 Indoor controller board receives
transmitted data at the same time,
compares the data, and when detecting
it, judges different data to be abnormal
30 continuous times. (Check code: E5)
OCH755
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 outdoor units
5 Short cycle of 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 All remote controllers are set
as "sub" remote controller. In
this case, E0 is displayed on
remote controller, and E4 is
displayed at LED (LED1, LED2)
on the outdoor controller circuit
board.
3 Miswiring of remote controller
4 Defective transmitting receiving
circuit of remote controller
5 Defective transmitting receiving
circuit of indoor controller board
of refrigerant address "0"
6 Noise has entered into the
transmission wire of remote
controller.
1 Defective remote controller
1 2 remote controller are set as
"main." (In the case of 2 remote
controllers)
2 Remote controller is connected
with 2 indoor units or more.
3 Repetition of refrigerant
address
4 Defective transmitting receiving
circuit of remote controller
5 Defective transmitting receiving
circuit of indoor controller board
6 Noise has entered into
transmission wire of 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 "10-6. TEST POINT
DIAGRAM" (Outdoor power circuit board).
4 Check 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 "10-4. 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 Set one of the remote controllers "main" if
there is no problem with the action above.
3 Check wiring of remote controller.
Refer to the indoor unit's Installation Manual
for remote controller connection.
If the cause of trouble is not in above 1–3,
4 Diagnose remote controllers.
a) When "OK" is displayed,
remote controllers have no problem.
Turn the power off, and on again to check.
If abnormality occurs again, replace indoor
controller board.
b) When "NG" is displayed,
Replace remote controller.
c) When "E3" or "ERC" is displayed, noise
may be causing abnormality.
Note: If the unit is not normal after replacing
indoor controller board in group control,
indoor controller board of address "0"
may be abnormal.
1 Replace remote controller.
1 Set a remote controller to main, and the other
to sub.
2 Remote controller is connected with only one
indoor unit.
3 The address changes to a separate setting.
4–6 Diagnose remote controller.
a) When "OK" is displayed, remote controllers
have no problem.
Turn the power off, and on again to check.
When becoming abnormal again, replace
indoor controller board.
b) When "NG" is displayed, replace remote
controller.
c) When "E3" or "ERC" is displayed, noise
may be causing abnormality.
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