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Refrigerant Circuit
SiBE18-821_C
66
Refrigerant Circuit
1. Refrigerant Circuit
1.1
Outdoor Unit
No. in
diagram
Symbol
Name
Major Function
A
M1C
Compressor motor
The compressor is operated on frequencies between 36 Hz and 195 Hz by using
inverter.
31 steps
D
M1F
M2F
Fan motor
Since the system is of air heat exchanging type, the fan is operated at 8-step rotation
speed by using the inverter.
E
Y1E
Electronic expansion valve
(Main)
While in heating operation, PI control is applied to keep the outlet superheated degree
of air heat exchanger constant.
F
Y3E
Electronic expansion valve
(Subcooling)
Pl control is applied to keep the outlet superheated degree of subcooling heat
exchanger constant.
G
Y2S
Solenoid valve (Hot gas
bypass valve)
Used to prevent the low pressure from temporary falling.
H
Y3S
Solenoid valve (Unload circuit) Used to the unloading operation of compressor.
M
Y1S
Four way valve
Used to switch the operation mode between cooling and heating.
N
S1NPH High pressure sensor
Used to detect high pressure.
O
S1NPL Low pressure sensor
Used to detect low pressure.
P
S1PH
High pressure switch
In order to prevent the increase of high pressure when an error occurs, this switch is
activated at high pressure of 4.0 MPa or more to stop the compressor operation.
T
—
Pressure regulating valve 1
(Receiver to discharge pipe)
This valve opens at a pressure of 4.0 MPa for prevention of pressure increase, thus
resulting in no damage of functional parts due to the increase of pressure in
transportation or storage.
1
R1T
Thermistor (Outdoor
temperature: Ta)
Used to detect outdoor temperature, correct discharge pipe temperature, and others.
2
R2T
Thermistor (Discharge pipe:
Tdi)
Used to detect discharge pipe temperature, make the temperature protection control of
compressor, and others.
3
R3T
Thermistor (Suction pipe 1:
Ts1)
Used to detect suction pipe temperature, keep the suction superheated degree
constant in heating operation, and others.
4
R4T
Thermistor (Outdoor heat
exchanger: Tb)
Used to detect liquid pipe temperature of outdoor heat exchanger, determine
defrosting operation, and others.
5
R5T
Thermistor (Suction pipe 2:
Ts2)
Used to the calculation of an internal temperature of compressor etc.
6
R6T
Thermistor (Subcooling heat
exchanger gas pipe: Tsh)
Used to control of subcooling electronic expansion valve.
7
R7T
Thermistor (Liquid pipe: Tl1)
Used to detect refrigerant overcharge in check operation, and others.
8
R8T
Thermistor (Liquid pipe 2: Tl2) Used to detect refrigerant over charge in check operation, and others.