Mitsubishi Electric MFZ-KT25VG-E1 Service Manual page 34

How to check miswiring and serial signal error
D
Turn OFF the power supply.
Turn ON the power supply.
Is there 230 V AC between
outdoor terminal block S1 and
S2?
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION INDICATOR
lamp light up? <Confirmation of the power
supply to the indoor unit>
Is the serial signal error indicated 6 minutes later?
· Turn OFF inverter-controlled lighting equipment.
· Turn OFF the power supply and then turn it ON again.
· Press EMERGENCY OPERATION switch.
Turn OFF the power supply.
Check once again if the indoor/outdoor
connecting wire is not wrongly connected.
Short-circuit the outdoor terminal block S2
and S3.
1
As for outdoor unit, refer to outdoor unit service manual.
OBH843A
Is there rated voltage of
230 V AC in the power
supply?
Yes
Yes
Yes
Yes
Is the serial
signal error
indicated 6
No
minutes later?
Yes
Check the power
supply.
No
Check the wiring.
No
No
Is there any miswiring,
poor contact, or wire
disconnection of the
No
indoor/outdoor
connecting wire?
· Reinstall either the unit or the light away
from each other.
· Attach a filter on receiving section of the indoor unit.
1. Miswiring may damage indoor electronic control
P.C. board during operation.
Be sure to confirm the wiring is correct before the
operation starts.
34
Correct them.
Yes
No