• When the valve is operating normally, it is free of vibration noise. If the valve locks or when it goes from
point E to A in the figure, it makes a louder noise than would be heard when there is an open phase.
• Check for abnormal sound/vibration by placing the metal tip of a screwdriver against the valve and the
handle side against your ear.
3) Troubleshooting
Symptom
Checking Criteria
Remedy
Circuit failure on
the microcomputer
Disconnect the connectors on the control board, and
connect LEDs to test the circuit as shown below.
resistance : 0.25W, 1kΩ
LED : DC15V, 20mA or more
Pulse signals are output for 10 seconds when the main
power is turned on. If there are LEDs that do not light up
at all or remain lit after the pulses are turned off, there is
a problem with the driving circuit.
Replace the
indoor control
board if driving
circuit failure is
detected.
Locked LEV
The motor will idle and make small clicking noise if it is
run while the LEV is locked. If this clicking noise is heard
both when the valve is fully closed and while it is being
opened, it indicates a problem.
Replace the LEV.
Disconnected or
shorted LEV motor
coils
Check the resistance between the coils with a tester
(white-red, yellow-brown, green-red, black-brown). If
LEV is disconnected or a short exists between LEV
coils, LEV resistance will read abnormal.The normal
range of resistance is 200 Ω±10%.
Replace the LEV.
Valve closure
failure (leaky
valve)
To check the LEV on the indoor unit, check the indoor
unit liquid pipe temperature that appears on the
operation monitor on the outdoor unit's multi control
board while operating the indoor unit in question in the
FAN mode and the other indoor units in the cooling
mode.
(A) Thermistor (TH22)
[
VIII
Troubleshooting ]
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HWE13010
GB
(4) Drain-up mechanism
Measure the resistance between the terminals with a tester.
(coil temperature 20°C[68°F])
(5) Drain float switch (CN4F)
Disconnect the connector, and measure the resistance between terminals with a tester.
Valve closure fail-
ure (leaky valve)
To check the LEV on the indoor unit, check the indoor unit liquid pipe temperature
that appears on the operation monitor on the outdoor unit's multi control board while
operating the indoor unit in question in the FAN mode and the other indoor units in
the cooling mode.
Replace the LEV
if the amount of
leakage is great.
(A)
Termistor (TH22)
Normally, the LEV is fully closed while the unit is in the FAN mode. If the valve is
leaky, liquid pipe thermistor reading will be lower than normal. If it is significantly
lower than the inlet temperature on the remote controller, valve closure failure is
suspected. If the amount of leakage is insignificant, replacement of LEV is unnec-
essary unless it is causing a problem.
Misconnections of
connectors or con-
tact failure
Perform a visual check for disconnected connectors.
Perform a visual check of lead wire color.
Disconnect the
connectors on
the control board
and perform a
continuity test.
Symptom
Checking Criteria
Remedy
(A)
LEV
Normal
Abnormal
340
Open or short
(A)
Moving part
(B)
Switch
(C)
Magnet
Position of the moving part
Normal
Abnormal
Up
Short
(any position but short)
Down
Open
(any position but open)
1
3
1
2
3
4
(A)
(A)
(B)
(C)
Replace the LEV
if the amount of
leakage is great.
PAC-AH001-1
37
© 2018 Mitsubishi Electric US, Inc.
