Mitsubishi MXZ-8B140VA Technical & Service Manual page 33

Abnormal point and detection method
Check code
Compressor overcurrent interruption
Abnormal if overcurrent DC bus or com-
pressor is detected after compressor
starts operating for 30 seconds.
UP
(4210)
Remote controller communication error
(Signal receiving error)
(1) Abnormal if any signal from IC of
refrigerant address "0" could not be
normally received for 3 minutes.
(2) Abnormal if sub remote controller could
E0
not receive any signal for 2 minutes.
(No display)
Remote controller communication error
(Transmitting error)
(1) Abnormal if sub remote controller could
E3
not find blank of transmission path for 6
(No display)
seconds.
(2) Abnormal if remote controller could not
finish transmitting 30 times continuously.
Indoor - branch box/branch box -
outdoor unit communication error
(Signal receiving error)
(Branch box/outdoor unit)
Abnormal if branch box/outdoor controller
E8
circuit board could not receive anything
(6840)
normally for 3 minutes.
Indoor - branch box/branch box -
outdoor unit communication error
(Transmitting error)
(Branch box/outdoor unit)
(1) Abnormal if "0" receiving is detected
30 times continuously though branch
E9
box/outdoor controller circuit board has
(6841)
transmitted "1".
(2) Abnormal if branch box/outdoor
controller circuit board could not find
blank of transmission path for 3 minutes.
Non defined check code
This code is displayed when non defined
EF
check code is received.
(6607
or
6608)
OCH480D
Case
1 Stop valve of outdoor unit is
closed.
2 Decrease of power supply volt-
age
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 out-
door controller board
7 Defective compressor
1 Defective communication circuit
of remote controller
2 Defective communication circuit
of indoor controller board of
refrigerant address "0"
3 Noise has entered into transmis-
sion line of remote controller.
4 All remote controllers are set
as "sub" remote controller. In
this case, E4 is displayed at
outdoor LED, and E0 is dis-
played at remote controller.
1 Defective communication circuit
of remote controller
2 Noise has entered into trans-
mission line of remote controller.
3 Two remote controllers are set
as "main."
(In case of 2 remote controllers)
1 Contact failure of indoor/out-
door unit connecting wire
2 Defective communication circuit
of branch box/outdoor controller
circuit board
3 Defective communication circuit
of indoor/branch box controller
board
4 Noise has entered into indoor–
branch box/branch box–
outdoor unit connecting wire.
1 Indoor–branch box/
branch box–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–
branch box/branch box–
outdoor unit connecting wire.
1 Noise has entered transmission
wire of remote controller.
2 Noise has entered Indoor–
branch box/branch box–
outdoor unit connecting wire.
3 Model name of remote
controller is PAR-S25A.
33
Judgment and action
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U·V·W phase) to com-
pressor. Refer to "8-7. TEST POINT DIAGRAM".
4 Check indoor/outdoor fan.
5 Solve short cycle.
6 Replace outdoor controller circuit board.
7 Check compressor. Refer to "8-6. HOW TO
CHECK THE PARTS".
Note:
Before the replacement of the outdoor con-
troller circuit board, disconnect the wiring for
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 volt-
age check with same performing frequency.
1–3 Diagnose remote controller.
Take actions as follows according to
diagnosis result.
a) When "RC OK" is displayed,
remote controllers have no problem.
Turn the power off, and on again to
check. If, "PLEASE WAIT" or "H0"
is displayed for 4 minutes or more,
replace indoor controller board.
b) When "RC NG" is displayed,
replace remote controller.
c) When "RC E3" or "ERC 00-66" is dis-
played, noise may be causing abnor-
mality.
4 Set a remote controller to main, and the other
to sub.
Note:
The descriptions above, 1-3, are for E0 and E3.
1 Check disconnection or looseness of indoor–
branch box/branch box – outdoor unit
connecting wire of indoor or branch box or
outdoor units.
2–4 Turn the power off, and on again to
check. Replace indoor controller board or
branch controller board or outdoor control-
ler circuit board if abnormality is displayed
again.
1 Check disconnection or looseness of
indoor–branch box/branch box–outdoor unit
connect-ing 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 branch
controller board or outdoor controller circuit
board if abnormality is displayed again.
3 Replace remote controller with MA remote
controller.