Mitsubishi Electric MUZ-EF-VG Series Service Manual page 39

D How to check miswiring and serial signal error
MUZ-EF Type
The connection information to the Multi series is stored
in the indoor unit. Refer to "Deleting the memorized
abnormal condition" described in 10-2.1 to clear the error
history. When the error history is being cleared, the con-
nection information also will be initialized. The indoor unit
will be compatible with a low-standby-power model after
initialization.
OK
Is there rated voltage between outdoor terminal block S1 and S2?
Wait for 2 or more minutes after the main power supply is turned on.
Touch S2 and S3 with tester probes and start the emergency operation.
When the emergency operation starts, does the rated voltage occur for 2
seconds between indoor terminal block S2 and S3?
Yes
Does the indoor OPERATION
INDICATOR lamp (left) blink
continuously 6 minutes after
No
the emergency operation
starts?
Yes
Does the outdoor LED blink 6
times?
No
Yes
Does DC (6V or more) occur
between indoor terminal block
No
S2 and S3?
Yes
Turn the main power supply
OFF.
Replace the indoor power P.C.
board.
Turn the main power supply ON.
Start the emergency operation.
Does the indoor OPERATION
INDICATOR lamp (left) blink
continuously 6 minutes after
No
the emergency operation
starts?
Yes
Does DC (20V or more) occur
between indoor terminal block
No
S2 and S3 ?
Yes
Replace the indoor electronic
control P.C. board.
OBH831C
Turn the main power supply
OFF.
Is there rated voltage in the power supply?
Yes
Check for incorrect indoor-outdoor connecting wiring.
Was the indoor unit ever connected to
the Multi (MXZ) series and operated
Yes
(turned on)?
• Turn OFF inverter-controlled lighting equipment.
• Turn OFF the power supply and then turn ON again.
• Press the emergency operation switch.
Is serial signal
error indicated 6
minutes later?
Yes
Turn the main power supply ON.
Yes
No
Does the outdoor LED
light up?
Yes
Confirm that the thermo-
stat is OFF and wiring is
not loose.
Replace the outdoor inverter
P.C. board. 1
Replace the outdoor inverter
P.C. board. 1
1.
Electric charge may remain
immediately after the main power
supply is turned OFF.
Perform the procedure after 3
minutes.
Repair completed.
Replace the outdoor inverter P.C. board. 1
Check the power supply.
No
No
• Reinstall either the unit or the light away from each other.
• Attach a filter on remote control receiving section of the indoor unit.
No
No
No
Wait for 2 or more minutes after the
main power supply is turned ON.
Touch CN102
emergency operation.
During the emergency operation,
does DC (2V or more [MSZ-
EF·VG-
[MSZ-EF·VG-
EF·VGK-
for 2 seconds between CN102
and JPG/CN102
electronic control P.C. board?
39
Check for miswiring, broken wires, and loose
wire connection between the main power
supply and outdoor terminal block S1 and
between the main power supply and outdoor
terminal block S2.
Turn the main power supply
OFF.
Turn the main power supply
ON.
and JPG/CN102
* with tester probes and start the
, ]/2V or less
E1 ET1
, , MSZ-
E2 ET2
, , ]) occur
E1 ET1 ER1
* on the indoor
Yes
Replace the
Replace the
indoor electronic
indoor power P.C.
control P.C.
board.
board.
* JGP: MSZ-EF·VG- ,
E1
CN102 : MSZ-EF·VG-
MSZ-EF·VGK-
No
ET1
, ,
E2 ET2
, ,
E1 ET1 ER1