Mitsubishi Electric PUHY-M200YNW-A1 Service Handbook page 283

[8-8 Troubleshooting LEV, FCV Problems ]
3) LEV valve closing and opening operation
Valve closed
Valve open
A
E
B
80 - 100 pulses
(2) Judgment methods and possible failure mode
Malfunction
mode
Microcomputer Disconnect the control board connector and connect
driver circuit fail- the check LED as shown in the figure below.
ure
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.
LEV mechanism If the LEV is locked, the drive motor runs idle, and
is locked makes a small clicking sound.
When the valve makes a closing and opening sound,
the valve has a problem.
Disconnected or Measure resistance between the coils (red - white, red
short-circuited -orange, brown - yellow, brown - blue) using a tester.
LEV motor coil They are normal if resistance is 150ohm
Faulty wire con- 1.
nections in the
connector or
2.
faulty contact
28
- chapter 8
D
C
* 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.
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.
Fully open *1
. 3000 pulses (Hydro unit LEV1)
Pulses
Judgment method
1 k
LED
Check for loose pins on the connector and check
the colors of the lead wires visually
Disconnect the control board's connector and
conduct a continuity check using a tester.
When the drive circuit has a
problem, replace the control
board.
6
5
4
3
2
1
Replace the LEV.
Replace the LEV coils.
10%.
Check the continuity at the
points where an error occurs.
Remedy
BS_08_E