Mitsubishi Electric MUH-GA50VB-E1 Service Manual page 32

When OPERATION INDICATOR lamp flashes 10-time.
Heating/ Cooling doesn't operate.
Check of LEV (Expansion valve)
E
Turn ON the power supply.
1 During pressing both the OPERATION SELECT
button and the TOO COOL button on the
remote controller at the same time,
press the RESET button.
2 First, release the RESET button.
And release the other two buttons since all LCD
in operation display section of the remote controller
is displayed after 3 seconds.
With remote controller set toward the indoor unit, press
OPERATE/ STOP (ON/ OFF) button and confirm one
beep tone.
LEV operates in full-opening
direction.
Do you hear the expansion
valve "click, click·······"?
Do you feel the expansion
valve vibrate on touching it?
No
Is LEV properly fixed to
the expansion valve?
Yes
Does the resistance of LEV have
the characteristics on 10-3?
No
Replace the
LEV.
When OPERATION INDICATOR lamp flashes 6-time.
Thermistors in the outdoor unit are abnormal.
Check of outdoor thermistor
F
w Disconnect the connectors CN661 and/ or CN662 from the deicer P.C. board.
(Check the characteristics of each thermistor.)
Defrost thermistor(RT61)
<MUH-GA80VB>
Discharge temperature
thermistor(RT62)
Measure
resistance
Turn OFF the
between CN 662
power supply.
1 and 2.
<MUH-GA80VB>
Ambient temperature
thermistor(RT63)
MUH-GA80VB
Yes
Ok
No
Properly fix the LEV to the
expansion valve.
Yes
Replace the
deicer P.C. board.
Measure
resistance
between CN 661
1 and 2.
Does the resistance
of thermistor have the
characteristics
on 10-5?
Replace the
thermistor.
Measure
resistance
between CN 662
3 and 4.
˚C
CLOCK
AMPM
AMPM
NOTE : After check of LEV, do the undermentioned operations.
1. Turn OFF the power supply and turn ON again.
2. Press the RESET button on the remote controller.
Connect CN661 and
CN662.
Turn ON the power
Yes
supply and press
the EMERGENCY
OPERATION switch.
No
32
Replace the deicer P.C.
board.
No
Does the unit operate
10 minutes or more?
Yes
Ok W.
W It is thought defective contact of the connector.