Table of Contents
Advertisement
5-16. 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
Actuating speed
Opening degree adjustment
Unit OFF
Remote controller ON
COOL · DRY MODE
During 1 to 5 minutes after compressor starts
HEAT MODE
During 1 to 15 minutes after compressor starts
More than COOL, DRY: 5/ HEAT: 15 minutes have
passed since compressor start-up
Thermostat OFF
Thermostat ON
Defrosting in HEAT mode
from minimum 33 pulse to maximum 500 pulse.
LEV opens 40 pulse/second and close 90 pulse/second
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.
LEV remains at maximum opening degree (reaches maxi-
mum opening degree approximate in 15 minutes after com-
pressor stops)
LEV is positioned. (first full-closed at zero pulse and then
positioned.)
LEV is fixed to standard opening degree according to opera-
tional frequency of compressor.
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.
LEV is adjusted to exclusive opening degree for thermostat
OFF.
LEV is controlled in the same way as that after the compres-
sor has started up.
LEV is adjusted to open 500 pulse.
70
Hide quick links:
Advertisement
Table of Contents
