Mitsubishi MSZ-FA-VA Service Technical Manual page 67

MXZ-3A/4A
The table below shows the role of Exclusive LEV and Receiver LEV in each operation mode.
Exclusive LEV
COOL
Receiver LEV
Exclusive LEV
HEAT
Receiver LEV
wIn COOL mode, the two indoor coil thermistor (one main and one sub) sense temperature ununiformity (super heat) at the
heat exchanger, and when temperature difference have developed, the indoor coil thermistors adjust LEV opening to dimin-
ish the super heat.This action is called Evaporation Temperature Protection.
The opening pulse of the Receiver LEV is fixed to the standard No.3 in cooling operation, and so is that of each Exclusive
LEV in heating operation.
However the opening pulse will be changed to the standard No.4 or No.5 when the discharge temperature protection or high-
pressure protection is working.
In addition to that, it will also be changed to standard No.2 or No.1 when the opening pulse of the each Exclusive LEV
becomes 100 pulse or less in cooling operation or so does that of Receiver LEV in heating operation.
<MXZ-3A54VA
Number of
operating
indoor units
Standard No.
1
2
3
4
5
<MXZ-4A80VA>
Number of
operating
indoor units
Standard No.
1
2
3
4
5
Downloaded from AC-Manual.com Manuals
Circulation
Amount
Control
Indoor heat Exclusive
exchanger
(MXZ-4A71VA, MXZ-4A80VA)
MXZ-4A71VA>
COOL
1 unit 2 units
200 150
300 320
400 360
450 410
500 500
COOL
1 unit 2 units
150 250
250 320
350 360
400 410
450 460
Discharge
Capacity
Temperature
Distribution
Protection
LEV
Receiver
LEV opening (pulse)
4 units
3 units 1 unit
(MXZ-4A71VA)
250 250
320 320
370 380
420 430
500 500
LEV opening (pulse)
3 units 4 units 1 unit
250 250
320 320
370 380
420 430
470 480
67
High
Pressure
Protection
Outdoor
heat
exchanger
Receiver
LEV
HEAT
2 units 3 units
120 120 120
140 140 140
160 160 160
220 220 220
280 280 280
HEAT
2 units 3 units
250 250 250
300 300 300
450 380 380
460 400 390
470 450 440
wEvaporation
Temperature
Protection
4 units
(MXZ-4A71VA)
120
140
160
220
280
4 units
240
290
380
390
430