Check Of Lev (Expansion Valve) - Mitsubishi Electric MUZ-A09YV-E1 Service Manual

Mitsubishi Electric ilmalämpöpumput korjaa ja huoltaa pääkaupunkiseudulla: Jäähdytinpalvelu RefGroup Oy
Outdoor unit does not operate at all or stops immediately due to over current.
Check of current-limiting resistor
K
When the current-limiting resistor is open, the rush current limiting relay (X64) may not work properly.
Start Does current-limiting resistor (R64) detect 10"?
Heating/Cooling does not work sufficiently.

Check of LEV (Expansion valve)

L
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
the 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
page 25?
No
Replace the LEV.
Outdoor base gets frozen.
Check of defrost heater
M
Check the following points before checking electric continuity.
1) Does the resistance of ambient temperature thermistor have the characteristics? (Refer to page 32.)
2) Is the resistance of defrost heater normal? (Refer to page 25.)
3) Does the heater protector remain conducted (not open)?
4) Are both ambient temperature thermistor and circuit of defrost heater securely connected to connectors?
In HEAT mode, for more than 5 minutes, let the ambient temperature thermistor continue to read 5: or less, and let the
defrost thermistor continue to read -1: or less.
Is there 230V AC between CN722 1 and 3 on the
power P.C. board?
Is the voltage between CN726 6(+)-3(-) on the
power P.C. board 0V DC? (Refer to page 33.)
Replace the inverter P.C. board.
Yes
Ok
Yes
Ok
No
Properly fix the LEV to the
expansion valve.
Measure each voltage between connector pins
of CN724 on the inverter P.C. board.
1.Pin3(-) Pin1(+)
Yes
2.Pin4(-) Pin1(+)
3.Pin5(-) Pin1(+)
4.Pin6(-) Pin1(+)
Is there about 3~5V AC between each?
NOTE: Measure the voltage by an analog tester.
Yes
Replace the
expansion valve.
<MUZ-A09YVH MUZ-A12YVH>
NOTE: In case both thermistors are more than the above
temperature, cool them with cold water etc...
No
No
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No ∞
Replace the power P.C. board.
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.
:
CLOCK
AMPM
AMPM
NOTE : After check of LEV, do the undermentioned
No
Replace the
inverter P.C. board.
Yes
No problem of the
power P.C. board.
Yes
Replace the power
P.C. board.
30
operations.
1. Turn OFF the power supply and
turn ON again.
2. Press the RESET button on the remote
controller.
3 6
230V AC
CN726
3
2
1
CN722
26H
H