Mitsubishi Electric CITY MULTI PEFY-P20VMAL Technical & Service Manual page 21

[ VII Troubleshooting ]
2) LEV operation
(e)
When the power is turned on, a pulse signal of 2200 pulses is output (valve closure signal), to bring the valve to position A.
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 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
Circuit failure on
the microcomputer
Locked LEV
Disconnected or
shorted LEV motor
coils
HWE0812B
(a)
(b)
(c)
(d)
Disconnect the connectors on the control board, and connect LEDs to test the cir-
cuit as shown below.
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.
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.
easure the resistance between the coils with a tester (red-white, red-orange,
brown-yellow, brown-blue). The normal range of resistance is 150 Ω 10%
(a) Close
(b) Open
(c) Fully open valve (2000 pulses)
(d) No. of pulses
(e) Extra tightning (80 - 100 pulse)
(f) Valve opening degree
Checking Criteria
6
5
4
3
2
1
1 k LED
- 16 -
Remedy
Replace the in-
door control
board if driving
circuit failure is
detected.
Replace the LEV.
Replace the LEV.
GB