Compressor Operation Control - Hitachi FSXN Series Service Manual

5 Control system
Control device
Purpose
Shut-off of high
High and low
and low pressure
pressure shut-off
in the cycle during
valve (SVG)
stoppage
Pd: Discharge pressure.
Ps: Suction pressure.
SH: Superheat.
SC: Supercooling.
TdSH: Superheat of discharge gas temperature.

5.1.2 Compressor operation control

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Compressor rotation control
The compressor rotation control is carried out to match its operation time in each of the outdoor units.
This control is carried out during the Thermo-OFF of the outdoor unit.
In case of switch-OFF or Thermo-OFF after 120 minutes of operation, the inverter compressor with the shortest operation
time will be preferably turned on.
N O T E
In order to carry out this function, at least two outdoor units are required.
The operating sequence of the compressor rotation is described below.
RAS-20FSXN
Outdoor unit 1
Last time
Currently
Next time
-I- Inverter compressor
RAS-(22-26)FSXN
Outdoor unit 1
-I-
Last time 1
Currently 2
Next time 1
-I- Inverter compressor
-C- Constant compressor
89
SMGB0065 rev. 1 - 12/2010
Cooling
Contents
Compressor
operating: ON
Compressor
stopped: OFF
Outdoor unit 2
-I-
1 2
2 1
1 2
Outdoor unit 2
-C- -I-
3 2
3 1
3 2
Heating
Heat recovery
Purpose Contents
Shut-off of high Compressor
and low pressure operating: ON
in the cycle during Compressor
stoppage stopped: OFF
Defrost
Contents
Open
5