Mitsubishi Electric NTXMMX A AA Series Service Manual page 32

When the left lamp of OPERATION INDICATOR lamp blinks ON and OFF in every 0.5-second
Outdoor unit does not operate.
How to check miswiring and serial signal error
D
Press the emergency operation switch once.
Is the serial signal error indicated 6 minutes later?
As for outdoor unit, refer to outdoor unit service manual.
OBHT802B
Turn OFF the power supply.
Is there rated voltage of
208/230 V AC in the power
supply?
Yes
Turn ON the power supply.
Is there 208/230 V AC between
outdoor terminal block S1 and
S2?
Yes
Does the left lamp of OPERATION INDICATOR
lamp light up? <Confirmation of the power
supply to the indoor unit>
Yes
Yes
· Turn OFF inverter-controlled lighting equipment.
· Turn OFF the power supply and then turn it ON again.
· Press the emergency operation switch.
Is the serial
signal error
indicated 6
minutes later?
Yes
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
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.
No
· 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.
32
Correct them.
Yes
No