Mitsubishi Electric NTXMMX A AA Series Service Manual page 33

When the left lamp of OPERATION INDICATOR lamp blinks 9 times
Indoor unit and outdoor unit do not operate.
Check of float sensor
E
Connect the lead wire.
*1 Refer to 9-5. when
float sensor can be checked.
Indoor electronic control P.C. board
C111
OBHT802B
Turn OFF the power supply and check
connectors CN145 and CN1N1 visually.
Are the lead wires
disconnected?
Yes
No
Disconnect float sensor from CN145 of
indoor electronic control P.C. board.
Measure the resistance between
Is the resistance 1Ω or
less? *1
Is there large amount
of water in drain pan?
Turn ON the power supply.
Press the emergency operation switch
(COOL) and perform emergency COOL
operation. Measure the voltage between
CN1N1 and
Is there 208/230 V AC
between CN1N1
?
Is the drain pump
operating?
Is the drain hose
clogged?
Replace the indoor
electronic control P.C. board.
CN1N1
CN145
Are there abnormality in
the soldering part of
connectors?
No
and .
Replace the indoor
Yes electronic control P.C. board.
No
Replace the float sensor.
No
Yes
.
Replace the indoor
and electronic control P.C. board.
No
Check power supply voltage.
Yes
Replace the drain pump.
No
Yes
Remove clog from drain
hose.
Yes
No
33
Replace the indoor
Yes
electronic control P.C. board.