Daikin VRV X RXQ6-48ANR Series, Service Manual, Page: 25 / 297

SiME341909EA Refrigerant Circuit (Piping Diagrams)
Part 2 Refrigerant Circuit 19
1. Refrigerant Circuit (Piping Diagrams)
1.1 Outdoor Unit
1.1.1 RXQ6/8/10/12AR
No. in
piping
diagram
Electric
symbol
Name Function
(1) M1C Compressor Compressor is operated in multi-steps according to Te.
(2) M1F Inverter fan The fan rotation speed is varied by using inverter.
(3) M2F
Inverter fan
(RXQ10/12AR only)
(4) Y2E
Electronic expansion valve
(Injection)
PI control is applied to keep the outlet superheating degree of subcooling
heat exchanger constant.
(5) Y4E
Electronic expansion valve
(Refrigerant auto charge)
Used to control refrigerant charging speed during refrigerant auto charge
operation and to stop refrigerant charge automatically.
(6) Y3S
Solenoid valve
(Oil return 1)
Used to control the amount of oil from the oil separator to the compressor.
(7) S1NPH High pressure sensor Used to detect high pressure.
(8) S1NPL Low pressure sensor Used to detect low pressure.
(9) S1PH
High pressure switch
(For M1C compressor)
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.
(10) —
Pressure regulating valve 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.
(11) —
Double tube heat exchanger
(Subcooling heat exchanger)
Used to subcool liquid refrigerant.
(12) —
Capillary tube Used to return the refrigerating oil separated through the oil separator to the
compressor.
(13) R1T
Thermistor
(Outdoor air: Ta)
Used to detect outdoor air temperature, correct discharge pipe temperature,
and others.
(14) R21T
Thermistor
(Discharge pipe: Tdi1)
Used to detect discharge pipe temperature, make the temperature
protection control of compressor, and others.
(15) R3T
Thermistor
(Suction pipe: Ts)
Used to detect suction pipe temperature, and for other purposes.
(16) R4T
Thermistor
(Heat exchanger liquid pipe: Tf)
This detects temperature of liquid pipe between the air heat exchanger and
check valve. Used to make judgments on the recover or discharge
refrigerants to the refrigerant regulator.
(17) R5T
Thermistor
(Subcooling heat exchanger
liquid pipe: Tsc)
This detects temperature of liquid pipe between the double tube heat
exchanger.
(18) R6T
Thermistor
(Subcooling heat exchanger
gas pipe: Tsh)
This detects temperature of gas pipe on the evaporation side of subcooling
heat exchanger. Used to exercise the constant control of superheating
degree at the outlet of subcooling heat exchanger.
(19) R8T
Thermistor
(Compressor body: Ti1)
Detects compressor surface temperature, this switch is activated at surface
temperature of 120°C or more to stop the compressor operation.