Mitsubishi Electric Mr.Slim MUZ-A09NA Service Manual page 55

L Check of LEV (Expansion valve)
MUZ-A09/12/15/17 MUY-A15/17
Turn ON the power supply.
<Preparation of the remote controller>
While pressing both OPERATION SELECT button
and TOO COOL button on the remote controller at the
same time, press RESET button.
First, release RESET button.
And release the other two buttons after all LCD in
operation display section of the remote controller is
displayed after 3 seconds.
Press OPERATE/STOP (ON/OFF) button of the remote
controller (the set temperature is displayed) with the
remote controller headed towards the indoor unit. 1
Expansion valve 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 coil properly fi xed to
the expansion valve?
Yes
Does the resistance of LEV
coil have the characteristics?
(Refer to 10-4.)
No
Replace the LEV coil.
NOTE: After check of LEV, do the undermentioned operations.
1. Turn OFF the power supply and turn ON again.
2. Press RESET button on the remote controller.
MUZ-A24 MUY-A24 MUZ-GA24 MUY-GA24
Turn ON power supply to the outdoor unit after checking
LEV coil is mounted to the LEV body securely.
Is "click - click" sound heard?
Or, do you feel vibration of the LEV coil with a hand?
Disconnect the connector CN795.
Is there normal resistance to LEV coil?
Replace the LEV coil.
OK
Yes
Properly fi x the LEV coil to the expansion valve.
No
Measure each voltage between connector pins of
CN724 on the inverter P.C. board.
1. Pin (-) — Pin (+)
2. Pin (-) — Pin (+)
Yes 3. Pin (-) — Pin (+)
4. Pin (-) — Pin (+)
Is there about 3 - 5 VAC between each?
NOTE: Measure the voltage with an analog tester.
Replace the expansion valve.
No
No
This figures show about MSZ-A09/12/15/17.
1. Regardless of normal or abnormal condition, a
short beep is emitted once the signal is received.
Yes
Normal
Yes
Replace the outdoor electronic control P.C. board.
Yes
55
Replace the inverter
No P.C. board.