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standard
specification
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 degrees set for each opera-
tional frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause
air conditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temper-
ature (Shell temperature) of the compressor, developing the unit’s performance.
Control range
from minimum 33 (MUZ-A09/12/15/17,MUY-A15/17)/ 59
(MUZ-A24/,MUY-A24) pulse to maximum 500 pulse.
Actuating speed LEV opens 40 pulse/second and 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.
Unit OFF LEV remains at maximum opening degree (reaches maxi-
mum opening degree approximate in 15 minutes after com-
pressor stops)
Remote controller ON LEV is positioned. (first full-closed at zero pulse and then
positioned.)
COOL · DRY MODE
During 1 to 5 minutes after compressor starts
HEAT MODE (MUZ)
During 1 to 15 minutes after compressor starts
LEV is fixed to standard opening degree according to opera-
tional frequency of compressor.
More than COOL, DRY: 5/ HEAT: 15 (MUZ) minutes
have passed since compressor start-up
LEV opening degree is corrected to get target discharge
temperature of compressor.
(For discharge temperature lower than target temperature,
LEV is corrected in closing direction.)
(For discharge temperature higher than target temperature,
LEV is corrected in opening direction.)
wIt 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.
Thermostat ON LEV is controlled in the same way as that after the compres-
sor has started up.
Defrosting in HEAT mode (MUZ) LEV is adjusted to open 500 pulse.
general operation
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