SiUS281117
Refrigerant Circuit
6
Refrigerant Circuit
1. Refrigerant Circuit
1.1
RZR18 / 24 / 30PVJU
RZQ18 / 24PVJU9
RZQ30PVJU
No. in
refrigerant
system
diagram
Electric
Symbol
Name
Major Function
A
M1C
Inverter compressor (INV.)
Inverter compressor is operated on frequencies between 52 Hz and 177 Hz by using
the inverter.
17 steps
D
M1F
Inverter fan
Because the system is an air heat exchange type, the fan is operated at 8-step rotation
speed by using the inverter.
E
Y1E
Electronic expansion valve
(Main: EV1)
While in heating operation, PI control is applied to keep the outlet superheated degree
of air heat exchanger constant.
G
Y2S
Solenoid valve (Hot gas: SVP) Prevents the low pressure from transient falling.
J
Y3S
Solenoid valve (Receiver gas
discharging: SVG)
Collects refrigerant to receiver.
M
Y1S
Four-way valve
Switches the operation mode between cooling and heating.
N
S1NPH High pressure sensor
Detects high pressure.
O
S1NPL Low pressure sensor
Detects low pressure.
P
S1PH
High pressure switch (For
INV. compressor)
In order to prevent the increase of high pressure when an error occurs, this switch is
activated at high pressure of 580 psi or more to stop the compressor operation.
S
—
Fusible plug
In order to prevent the increase of pressure when abnormal heating is caused by fire
or others, the fusible part of the plug is molten at a temperature of 158 to 167°F to
release the pressure into the atmosphere.
T
—
Pressure regulating valve 1
(Receiver to discharge pipe)
This valve opens at a pressure of 580 psi 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 air: Ta)
Detects outdoor air temperature, correct discharge pipe temperature, and others.
2
R2T
Thermistor (Discharge pipe:
Tdi)
Detects discharge pipe temperature, make the temperature protection control of
compressor, and others.
3
R3T
Thermistor (Suction pipe 1:
Ts1)
Detects suction pipe temperature, keep the suction superheated degree constant in
heating operation, and others.
4
R4T
Thermistor (Heat exchanger
deicer: Tb)
Detects liquid pipe temperature of air heat exchanger, determine defrosting operation,
and others.
5
R5T
Thermistor (Suction pipe 2:
Ts2)
Calculates internal temperature of compressor.
10
R10T
Thermistor (Radiation fin)
•
Outdoor unit fan speed control.
•
Inverter radiation fin temperature control.
•
Pressure difference control.
