[8-8 Troubleshooting LEV, FCV Problems ]
28
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chapter 8
BS_08_E
8 Troub
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sho
oting Bas
ed on Ob
ser
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Sy
mp
toms
3) LEV valve closing and opening operation
(2) Judgment methods and possible failure mode
When the valve operates smoothly, no sound from LEV or no vibration
occurs, however, when the pulses change from E to A in the chart or
the valve is locked, a big sound occurs.
*Whether a sound is generated or not can be determined by
holding a screwdriver against it, then placing your ear against the handle.
*1 The LEV opening may become greater depending on the operation status.
* Upon power on, the Hydro unit circuit board sends 3200 Hz pulse
signals to the LEV (Hydro unit LEV1) to determine the valve
position and bring the valve to the position as indicated by A in the diagram.
.3000 pulses (Hydro unit LEV1)
V
alve opening (refrigerant flow rate)
Valve closed
Valve open
E
B
80 - 100 pulses
Pulses
Fully open *1
A
C
D
Malfunction
mode
Judgment method
Remedy
Microcomputer
driver circuit fail-
ure
Disconnect the control board connector and connect
the check LED as shown in the figure below.
resistance : 0.25W 1k
LED : DC15V 20mA or more
When the main power is turned on, the indoor unit cir-
cuit board outputs pulse signals to the indoor unit LEV
for 10 seconds.
If any of the LED remains lit or unlit, the drive circuit is
faulty.
When the drive circuit has a
problem, replace the control
board.
LEV mechanism
is locked
If the LEV is locked, the drive motor runs idle, and
makes a small clicking sound.
When the valve makes a closing and opening sound,
the valve has a problem.
Replace the LEV.
Disconnected or
short-circuited
LEV motor coil
Measure resistance between the coils (red - white, red
-orange, brown - yellow, brown - blue) using a tester.
They are normal if resistance is 150ohm
10%.
Replace the LEV coils.
Faulty wire con-
nections in the
connector or
faulty contact
1.
Check for loose pins on the connector and check
the colors of the lead wires visually
Check the continuity at the
points where an error occurs.
2.
Disconnect the control board's connector and
conduct a continuity check using a tester.
6
5
4
3
2
1
1 k
LED
0000004986.BOOK 28 ページ 2019年5月9日 木曜日 午後6時22分
Summary of Contents for City Multi CMH-WM250V-A
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