Mitsubishi Electric PUHY-HP120TNU-A, Service Handbook

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[8-8 Troubleshooting LEV Problems ]
26
- chapter 8 HWE18240_GB
8 Troubleshooting Based on Observed Symptoms
3) Pulse signal output and valve operation
4) LEV closing and opening operation
Output state Output
(phase)
number
1 2 3 4
1 ON OFF OFF ON
2 ON ON OFF OFF
3 OFF ON ON OFF
4 OFF OFF ON ON
Output pulses change in the following orders when the
Valve is closed; 1 2 3 4 1
Valve is open; 4 3 2 1 4
*1. When the LEV opening angle does not change,
all the output phases will be off.
*2. When the output is open phase or remains ON,
the motor cannot run smoothly, and rattles and vibrates.
*Upon power on, the indoor unit circuit board sends a 2200 pulse
signal to the indoor unit LEV and a 3200 pulse signal to the outdoor
unit LEV to determine the valve position and always brings 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.
V
alve opening (refrigerant flow rate)
Valve closed
Valve open
E
B
80 - 100 pulses
Pulses
Fully open
.1400 pulses (indoor unit LEV) *1
.2100 pulses (outdoor unit LEV) *1
A
C
D