Refrigerant Circuit (Piping Diagram)
SiUS30-1301
14
Refrigerant Circuit
1. Refrigerant Circuit (Piping Diagram)
1.1
RWEYQ72PTJU / RWEYQ
8
4PTJU
RWEYQ72PYDN / RWEYQ
8
4PYDN
No. in
Refrigerant
System
Diagram
Electric
Symbol
Name
Major Function
A
M1C
Inverter compressor
Inverter compressor is operated on frequencies between 52 Hz and 230
Hz by using the inverter. The number of operating steps is as follows.
RWEYQ72P, 84P: 22 steps
B
Y1E
Electronic expansion valve (Main)
In cooling: High pressure control
In heating or simultaneous cooling/heating operation:
• When the heat exchanger is used as the evaporator : SH control
• When the heat exchanger is used as the condensing : High pressure
control
C
Y3E
Electronic expansion valve (Subcooling:
EVB)
PI control is applied to keep the outlet superheated degree of subcooling
heat exchanger constant.
D
Y1S
Solenoid valve (Hot gas: SVP)
Prevents the low pressure from transient falling.
E
Y2S
Solenoid valve (Oil return of water heat
exchanger: SVE)
Collects the refrigerant oil from water heat exchanger.
F
Y3S
Solenoid valve (Receiver gas charging: SVL)
Maintains high pressure while in cooling at low water temperature. And
also used to prevent the accumulation of refrigerant in non-operating
condensing units in the case of multiple condensing unit system.
G
Y4S
Solenoid valve (Receiver gas vent: SVG)
Collects the refrigerant to receiver.
H
Y5S
Four-way valve (Main: 20S1)
Changes the operation into cooling, heating or simultaneous cooling/
heating operation.
I
Y6S
Solenoid valve (Non-operating unit liquid
pipe closing: SVSL)
Prevents the accumulation of refrigerant in non-operating condensing
units in the case of multiple condensing unit system.
J
Y7S
Four-way valve (Sub: 20S2)
Changes the water heat exchanger intocondensing or evaporator.
K
S1NPH
High pressure sensor
Detects high pressure.
L
S1NPL
Low pressure sensor
Detects low pressure.
M
S1PH
High pressure switch (For INV. compressor)
Prevents 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.
N
–
Fusible plug
Prevents 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.
O
–
Pressure regulating valve (Liquid pipe to
discharge pipe)
This valve opens at a pressure of 580 psi or more 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
Radiation fin thermistor
• Condensing unit fan speed control.
• Inverter radiation fin temperature control.
• Pressure difference control.
2
R2T
Suction pipe thermistor (Ts)
Detects suction pipe temperature, keep the suction superheated degree
constant in heating, and others.
3
R3T
Discharge pipe thermistor (Tdi)
Detects discharge pipe temperature, make the temperature protection
control of compressor, and others.
4
R4T
Heat exchanger gas pipe thermistor (Tg)
Detects gas pipe temperature of water heat exchanger.
5
R5T
Subcooling heat exchanger outlet pipe
thermistor (Tsh)
Detects gas pipe temperature on the evaporating side of subcooling heat
exchanger, keep the superheated degree at the outlet of subcooling heat
exchanger constant, and others.
6
R6T
Receiver outlet liquid pipe thermistor (Tl)
Detects receiver outlet liquid pipe temperature, prevent the drift between
condensing units while in heating in the case of multiple condensing unit
system, and others.