Check Of Lev (Expansion Valve); Check Of Outdoor Thermistor - Mitsubishi Electric MSH-18RV Service Manual

Check of LEV (Expansion valve)

I
Heating/ Cooling doesn't operate.
1 During pressing OPERATION SELECT button
on remote controller, press RESET button.
2 First, release RESET button.
(Confirm all displays of remote controller.)
3 Then release OPERATION SELECT button.
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 LEV "click,
click·······"?
Do you touch LEV and feel
it vibrate?
No
Is LEV coil properly fixed to
the body?
Yes
Does the resistance of LEV coil
have the characterictics?
No
Replace the
LEV coil.

Check of outdoor thermistor

J
Thermistors in the outdoor unit are abnormal.
w Disconnect the connectors CN661 and/ or CN662 from the deicer P.C. board.
(Check the characteristics of each thermistor.)
Defrost thermistor(RT61)
<MSH-30RV only>
Discharge temperature
thermistor(RT62)
Measure
resistance
Turn OFF the
between CN 662
power supply.
1 and 2.
<MSH-24/30RV only>
Ambient temperature
thermistor(RT63)
Yes
Ok
No
Properly fix LEV coil to
the body.
Yes
Replace the
deicer P.C. board.
Measure
resistance
between CN 661
1 and 2.
Does the resistancs
of thermistor have
the characteristics
on page 69 or 70?
Replace the
thermistor.
Measure
resistance
between CN 662
3 and 4.
<MSH-30RV only>
Characteristics of LEV coil
LEV (CN724)
WHT–RED
RED–ORN
YLW–BRN
BRN–BLU
NOTE : After check of LEV, do the undermentioned operations.
1. Turn OFF the power supply of the unit 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
W1. It is thought defective contact of the connector.
66
1 During pressing OPERATION SELECT
button on remote controller, press
RESET button.
2 First, release RESET button.
(Confirm all displays of remote controller.)
3 Then release OPERATION SELECT button.
˚C
CLOCK
AMPM
AMPM
Resistance
30.3 " ~ 37.0 "
Replace the deicer P.C.
board.
No
Does the unit operate
10 minutes or more?
Yes
Ok W1.