Expansion Valve Control (Lev Control); Outline Of Lev Control - Mitsubishi Electric Mr.Slim MSZ09UN Service Manual

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

During 2 to 13 minutes after compressor starts

More than 13 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 frequen-

cy 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 starts to open every 3 pulse/sec.

from

the same opening degree as that when the Unit turned OFF

(and becomes full-opened after approx. 15 minutes.)

LEV is controlled in the same way as that is after the com-

pressor has started up.

LEV is adjusted to open 500 pulse.

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