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MITSUBISHI ELECTRIC MXZ-32SV User Manual

Page 20

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Linear expansion valve (LEV) is controlled by "Thermostat ON" commands given from each unit.

• The standard opening is on the straight line, which connects an each standard point in the section where divided

into seven according to the operation frequency of compressor as shown in the figure below.
(LEV opening is controlled in proportion to the operation frequency.)

Note: Opening is adjusted at the standard opening according to the indoor unit conditions.

However, inclination of standard opening in each point of opening does not change with the original curve.

• Add opening provided in Difference in Capacity in the table below to the standard opening from 1 to 8,

when capacity of the indoor unit is excluding code 1.

• Add opening provided in Difference in Operation number in the table below to determined LEV opening for

each indoor unit, when 2, 3 or 4 indoor units are operated at the same time.

Note: Even when the adjusted standard opening exceeds the driving range from 59 to 500 pulse, actual

driving output opening is in a range from 59 to 500 pulse.

< Calculation example of LEV opening >
Cool operation: Compressor frequency 70Hz: 2 unit ON: 18class
(170-150)

p

(80-60)

o

(70-60)+150+75-30=205 pulse

Determination of LEV standard opening in each indoor unit

When outdoor unit is operating,

some indoor unit stops and

some operates.

• LEV opening for each indoor unit is determined by adding adjustment in accordance

with the number of operating unit and the capacity class to standard opening, based
on the operation frequency:
Ex.) Opening 130 pulse in standard opening 1

Minimum 80 pulse, Maximum 205

pulse. (Capacity code 4 at 1 unit operation) (Capacity code 1 at 4 unit operation)

• After starting operation, adjustment in accordance with intake super heat, discharge

temperature is included in standard opening.

w

1

Note: LEV opening in each frequency at DRY operation and COOL operation is the

same. However, velocity and compressor operation frequency controls are
different. See 11-2 Operational frequency range
(As far as the indoor unit velocity control goes, refer to DRY operation in
MICROPROCESSOR CONTROL in the indoor unit service manual.)

• LEV opening for each indoor unit is determined by adding adjustment in accordance

with the number of operating unit and the capacity class to standard opening, based
on the operation frequency:
Ex.) Opening 120 pulse in standard opening 1

Minimum 70 pulse, Maximum 165

pulse. (Capacity code 4 at 1 unit operation) (Capacity code 1 at 4 unit operation)

• After starting operation, opening becomes the one that adjustment in accordance

with discharge temperature was added to basic opening.

w

1

Thermostat ON in HEAT mode

LEV opening

Thermostat OFF in

COOL or DRY mode

Thermostat OFF in HEAT mode

Stop of all indoor unit

Indoor unit status

COOL : 5 pulse (full closed)
HEAT : 59 pulse (slightly opened)

Thermostat ON in

COOL or DRY mode

Opening before stop

500 pulse in 15 minutes

When the outdoor unit operation (When the other indoor unit operate): 5 pulse.
When outdoor unit stops. (When the other indoor unit stops or thermo off):
Maintain LEV opening before stop

500 pulse in 15 minutes

• When the outdoor unit operates. (When the other indoor unit operates): 59 pulse
• When the outdoor unit stops. (When the other indoor unit stops or thermo off):

Maintain LEV opening before stop

500 pulse in 15 minutes.

w

1 LEV opening when the outdoor unit operating: Upper limit 500, Lower limit 59

7

20

40

60

80

100

120

140

Operation frequency of compressor (Hz) : F

120

130

140

150

160

170

180

190

200

210

220

LEV opening (Pulse)

Standard opening

1

2

3

4

5

6

7

8

COOL

HEAT

11-1.LEV control

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