Indoor Unit - Mitsubishi Electric MFZ-KJ25VE Service Manual

MUFZ-KJ50
Check for incorrect indoor-outdoor connecting wiring.
Is there rated voltage between outdoor terminal block S1 and S2?
Wait for 2 or more minutes after the 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 sec-
onds between indoor terminal block S2 and S3?
Yes
Does the left lamp of the OPERA-
TION INDICATOR lamp on the
indoor unit blink continuously
6 minutes after the emergency
operation starts?
Yes
Does the outdoor LED blink 6
times?
Yes
Does DC (more than 0 V) occur
between indoor terminal block S2
and S3?
Yes
Turn the power supply OFF.
Replace the indoor electronic
control P.C. board.
Turn the power supply ON.
Start the emergency operation.
Does the left lamp of the OPERA-
TION INDICATOR lamp on the
indoor unit blink continuously
6 minutes after the emergency
operation starts?
Yes
Replace the outdoor inverter P.C.
board and the outdoor relay P.C.
board. 1
OBH666A
Turn the power supply OFF.
Is there rated voltage in the power supply?
Yes
A
B Turn the power supply ON.
Yes
Does DC (10 V or more) occur
No
between L68A and L68B on the
outdoor relay P.C. board?
Yes
Replace the outdoor relay P.C.
board. 1
Replace the outdoor inverter P.C.
No
board and the outdoor relay P.C.
board. 1
Replace the outdoor inverter P.C.
No
board. 1
1.
Electric charge may remain immediately
after the power supply is turned OFF.
Perform the procedure after 3 minutes.
No
Repair has been completed.
Check the power supply.
No
• Turn OFF inverter-controlled lighting equipment.
• Turn OFF the power supply and then turn ON again.
• Press EMERGENCY OPERATION switch.
Is serial signal
error indicated 6
minutes later?
Yes
B
Check for miswiring, broken wires, and loose wire
No
connection between the power supply and outdoor
terminal block S1 and between the power supply and
outdoor terminal block S2.
No
No
Replace the outdoor inverter P.C.
board and the outdoor relay P.C.
board. 1
28
NOTE: Refer to the indoor unit service manual.
A
• Reinstall either the unit or the light
away from each other.
• Attach a fi lter on remote control
No
receiving section of the indoor unit.
Replace the indoor electronic
control P.C. board.