Daikin RXYQ-TA Series Service Manual page 26

Refrigerant Circuit
1.1.3 RXYQ144/168TAYDU, RXYQ144/168TATJU
No. in
Electric
piping
symbol
diagram
(1) M1C
Inverter compressor
(2) M2C
(3) M1F
Inverter fan
(4) M2F
Electronic expansion valve
(5) Y1E
(Main)
Electronic expansion valve
(6) Y2E
(Injection)
Solenoid valve
(7) Y1S
(Four way valve)
Solenoid valve
(8) Y2S
(Accumulator oil return)
(9) Y3S Solenoid valve (Oil return 1)
(10) Y4S Solenoid valve (Oil return 2)
(11) S1NPH High pressure sensor
(12) S1NPL Low pressure sensor
High pressure switch
(13) S1PH
(For M1C compressor)
High pressure switch
(14) S2PH
(For M2C compressor)
(15) — Pressure regulating valve
(16) — Subcooling heat exchanger
(17) —
Capillary tube
(18) —
Thermistor (Outdoor air)
(19) R1T
(A1P)
Thermistor
(20) R1T
(Radiation fin) (A3P)
Thermistor
(21) R21T
(M1C discharge pipe)
Thermistor
(22) R22T
(M2C discharge pipe)
(23) R3T Thermistor (Accumulator inlet) Used to detect gas pipe temperature at the accumulator inlet.
Thermistor (Heat exchanger
(24) R4T
liquid pipe)
Thermistor (Subcooling heat
(25) R5T
exchanger liquid pipe)
Thermistor (Subcooling heat
(26) R6T
exchanger gas pipe)
Thermistor
(27) R7T
(Heat exchanger deicer)
13
Name
Inverter compressor is operated in multi-steps according to Te.
Because the system is an air heat exchange type, the fan is operated at 10-step rotation
speed by using the inverter.
Fully open during cooling operation.
PI control is applied to keep the outlet superheated degree of subcooling heat exchanger
constant.
Used to switch the operation mode between cooling and heating.
Used to return oil from the accumulator to the compressor.
Used to control the amount of oil from the oil separator to the compressor.
Used to detect high pressure.
Used to detect low pressure.
In order to prevent the increase of high pressure when an error occurs, this switch is
activated at high pressure of 4.0 MPa (580 psi) or more to stop the compressor operation.
This valve opens at a pressure of 4.0 MPa (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.
Used to subcooling liquid refrigerant from the electronic expansion valve.
Used to return the refrigerating oil separated through the oil separator to the compressor.
Used to detect outdoor air temperature, correct discharge pipe temperature, and others.
RXYQ144/168TATJU only
• Used for outdoor unit fan speed control.
• Used for inverter radiation fin temperature control.
• Used for pressure difference control.
Used to detect discharge pipe temperature, make the temperature protection control of
compressor, and others.
This detects temperature of liquid pipe between the air heat exchanger and main
electronic expansion valve. Used to make judgements on the recover or discharge
refrigerants to the refrigerant regulator.
This detects temperature of liquid pipe between the main electronic expansion valve and
subcooling heat exchanger.
This detects temperature of gas pipe on the evaporation side of subcooling heat
exchanger. Used to exercise the constant control of superheated degree at the outlet of
subcooling heat exchanger.
Used to detect liquid pipe temperature of air heat exchanger.
Function
SiUS341615E
Refrigerant Circuit