Troubleshooting - Mitsubishi Electric PUD-SWM60VAA Service Manual

9

TROUBLESHOOTING

9-1. TROUBLESHOOTING
<Check code displayed by self-diagnosis and actions to be taken for service (summary)>
Present and past check codes are logged, and they can be displayed on the control board of outdoor unit. Actions to be taken
for service, which depends on whether or not the trouble is reoccurring in the field, are summarized in the table below. Check
the contents below before investigating details.
Unit conditions at service
The trouble is reoccurring.
The trouble is not reoccurring.
9-2. SELF-DIAGNOSIS ACTION TABLE
<Abnormalities detected when the power is turned on>
Check code Abnormal point and detection method
None
OCH756
Check code
Displayed
Not displayed
Logged
Not logged
1 No voltage is supplied to
terminal block (TB1) of outdoor
unit.
a) Power supply breaker is
turned off.
b) Contact failure or
disconnection of power
supply terminal
c) Open phase (L or N phase)
2 Electric power is not charged
to power supply terminal of
outdoor power circuit board.
a) Contact failure of power
supply terminal
b) Open phase on the outdoor
power circuit board
— 3 Electric power is not supplied
to outdoor controller circuit
board.
a) Disconnection of connector
(CNDC)
4 Disconnection of reactor (DCL
or ACL)
5 Disconnection of outdoor noise
filter circuit board or parts
failure in outdoor noise filter
circuit board
6 Defective outdoor power circuit
board
7 Defective outdoor controller
circuit board
Actions to be taken for service (summary)
Judge what is wrong and take a corrective action according
to "9-2. SELF-DIAGNOSIS ACTION TABLE".
Conduct troubleshooting and ascertain the cause of the trouble
according to "9-3. TROUBLESHOOTING OF PROBLEMS".
1 Consider the temporary defects such as the work of protection
devices in the refrigerant circuit including compressor, poor
connection of wiring, noise, etc.
Re-check the symptom, and check the installation environ-
ment, refrigerant amount, weather when the trouble occurred,
matters related to wiring, etc.
2 Reset check code logs and restart the unit after finishing ser-
vice.
3 There is no abnormality in electrical component, controller
board, remote controller, etc.
1 Re-check the abnormal symptom.
2 Conduct troubleshooting and ascertain the cause of the trouble
according to "9-3. TROUBLESHOOTING OF PROBLEMS".
3 Continue to operate unit for the time being if the cause is not
ascertained.
4 There is no abnormality concerning of parts such as electrical
component, controller board, remote controller, etc.
Note: Refer to indoor unit section for code P, code E, and Code L.
Cause
1 Check following items.
a) Power supply breaker
b) Connection of power supply terminal block
c) Connection of power supply terminal block
2 Check following items.
a) Connection of power supply terminal block
b) Connection of terminal on outdoor power
3 Check connection of the connector (CNDC)
on the outdoor controller circuit board.
Check connection of the connector, CNDC on
the outdoor power circuit board(V)/the noise
filter(Y). Refer to "9-6.TEST POINT
DIAGRAM".
4 Check connection of reactor. (DCL or ACL)
Refer to "9-6.TEST POINT DIAGRAM".
5 a) Check connection of outdoor noise filter cir-
b) Replace outdoor noise filter circuit board.
6 Replace outdoor power circuit board.
7 Replace controller board (When items above
are checked but the units cannot be repaired).
22
Judgment and action
(TB1)
(TB1)
(TB1)
circuit board
Check connection of the connector LI or NI.
Refer to "9-6.TEST POINT DIAGRAM".
cuit board.
Refer to "9-6.TEST POINT DIAGRAM".