Mitsubishi Electric MUZ-HJ25VA-E1 Service Manual page 29

J Check of power supply
Disconnect the connector (CN61)
between compressor and power
module.
Turn ON power supply and press
EMERGENCY OPERATION switch.
Does the upper lamp of OPERATION
INDICATOR lamp on the indoor unit
light up?
Yes
Is there voltage 250 - 370 VDC
between DB61 (+) and DB61 (–) on
the inverter P.C. board?
(Refer to 11-6.1.)
Check the electric parts in main circuit.
K Check of LEV (Expansion valve)
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.
Hold down the other two buttons for another 3
seconds. Make sure that the indicators on the LCD
screen shown in the right fi gure are all displayed.
Then release the buttons.
Press OPERATE/STOP (ON/OFF) button of the remote
controller (the set temperature is displayed) with the
remote controller headed towards the indoor unit.
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 11-4.)
No
Replace the LEV coil.
NOTE : After check of LEV, do the undermentioned operations.
1. Turn OFF the power supply and turn ON it again.
2. Press RESET button on the remote controller.
OBH648
No
Yes
No
1
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 (+)
3. Pin (-) — Pin (+)
Yes
4. Pin (-) — Pin (+)
Is there about 3 ~ 5 VAC between each?
NOTE: Measure the voltage by an analog
tester.
Replace the expansion valve.
Rectify indoor/outdoor
connecting wire.
Yes
Is there voltage 230 VAC
between the indoor terminal
block S1 and S2?
Dose LED on the inverter P.C.
board light up or fl ash? (Refer
to 11-6.1.)
Yes
If light up, OK.
If fl ash, refer to 11-3.
1. Regardless of normal or abnormal condition, a short beep
is emitted once the signal is received.
OK
Yes
29
250 - 370 VDC
DB61
Inverter P.C. board
(Solder side)
Replace the indoor
electronic control P.C.
No
board.
Replace the inverter
No
P.C. board.
Replace the inverter P.C.
No board.