Mitsubishi Electric MSZ-A09RV-E1 Service Manual page 34

9-11 .Electronic 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
operational 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 temperature
(Shell temperature) of the compressor, developing the unit's performance.
(2)Specification of LEV control
Control range
Actuating speed
Opening degree adjustment
Unit OFF
Remote controller ON
During 2 to 15 minutes after compressor starts
More than 15 minutes have passed since compressor
start-up
Thermostat OFF
Thermostat ON
Defrosting in HEAT mode
from min. 33 pulse to max. 500 pulse.
LEV opens 40 pulse/sec. and close 90 pulse/sec.
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 max. opening degree (reaches max. opening
degree approx. 15 minutes after compressor stops)
LEV is positioned. (first full-closed at zero pulse and then
positioned.)
Opening degree is adjusted according to standard opening
degree.
(Standard opening degree is set for each rotational
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
temperature, depending on operating conditions.
LEV starts to open every 3 pulse/sec.
from
the same opening degree as that when the Unit turned IFF
(and becomes full-opened after approx. 15 minutes.)
LEV is controlled in the same way as that is after the
compressor has started up.
LEV is adjusted to open 350 pulse.
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