Mitsubishi Electronics MUZ-FDNA - U Manuel D’Utilisation
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2-9. EXPANSION VALVE CONTROL (LEV CONTROL)
(1) Outline of LEV control
The LEV basic control is comprised of setting LEV opening degree to the standard opening °F set for each operational
frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause air con-
ditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temperature
(Shell temperature) of the compressor, developing the unit’s performance.
The LEV basic control is comprised of setting LEV opening degree to the standard opening °F set for each operational
frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause air con-
ditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temperature
(Shell temperature) of the compressor, developing the unit’s performance.
Standard specification
Control range
Minimum
: 33 pulse (MUZ-A09/12/15/17 MUY-A15/17)
59 pulse (MUZ-A24 MUY-A24)
54 pulse (MUZ-FD)
58 pulse (MUZ-D MUY-D)
54 pulse (MUZ-FD)
58 pulse (MUZ-D MUY-D)
Maximum
: 500 pulse
Actuating speed
Open : 40 pulse/second
Close : 90 pulse/second.
Close : 90 pulse/second.
Opening degree adjustment
LEV opening degree is always adjusted in opening direction.
(When reducing the opening degree, LEV is once over-closed,
and then adjusted to the proper degree by opening.
(When reducing the opening degree, LEV is once over-closed,
and then adjusted to the proper degree by opening.
General operation
Unit OFF
LEV remains at maximum opening degree (reaches maximum
opening degree approximate in 15 minutes after compressor
stops)
opening degree approximate in 15 minutes after compressor
stops)
Remote controller ON
LEV is positioned. (first full-closed at zero pulse and then posi-
tioned.)
tioned.)
COOL · DRY MODE
During 1 to 5 minutes after compressor starts
During 1 to 5 minutes after compressor starts
HEAT MODE
During 1 to 15 minutes after compressor starts
During 1 to 15 minutes after compressor starts
LEV is fixed to standard opening degree according to opera-
tional frequency of compressor.
tional frequency of compressor.
More than 5 (COOL, DRY), 15 (HEAT (MUZ)) minutes
have passed since compressor start-up
have passed since compressor start-up
LEV opening degree is corrected to get target discharge tem-
perature of compressor.
(For lower discharge temperature than target temperature,
LEV is corrected in closing direction.)
(For higher discharge temperature than target temperature,
LEV is corrected in opening direction.)
perature of compressor.
(For lower discharge temperature than target temperature,
LEV is corrected in closing direction.)
(For higher discharge temperature than target temperature,
LEV is corrected in opening direction.)
It may take more than 30 minutes to reach target tempera-
ture, depending on operating conditions.
Thermostat OFF
LEV is adjusted to exclusive opening degree for thermostat
OFF.
OFF.
Thermostat ON
LEV is controlled in the same way as that after the compres-
sor has started up.
sor has started up.
Defrosting in HEAT mode
LEV is adjusted to open 500 pulse.