Daikin RXSQ24TAVJU Service Manual page 23

SiUS331708EA
1.1.2 RXSQ48TAVJU
No. in
piping Symbol
diagram
(1) M1C Inverter compressor
(2) M1F Inverter fan
Electronic expansion valve
(3) Y1E
(Main)
(4) Y1S Four way valve
(5) Y3S Solenoid valve (Injection)
(6) S1NPH High pressure sensor
(7) S1NPL Low pressure sensor
(8) S1PH High pressure switch
(9) — Fusible plug
Pressure regulating valve 1
(10) —
(Receiver to discharge pipe)
(11) R1T Thermistor (Outdoor air)
(12) R2T Thermistor (Discharge pipe)
(13) R3T Thermistor (Suction pipe 1)
Thermistor (Heat exchanger
(14) R4T
deicer)
(15) R5T Thermistor (Suction pipe 2)
(16) R7T Thermistor (Liquid pipe)
(17) FINTH Thermistor (Radiation fin)
Refrigerant Circuit
Name
Inverter compressor is operated on frequencies between 15 rps and 109 rps by using the
inverter.
Because the system is of an air heat exchange type, the fan is operated at 8-step rotation
speed by using the inverter.
While in heating operation, PI control is applied to keep the outlet superheated degree of
air heat exchanger constant.
Used to switch the operation mode between cooling and heating.
Used to protect discharge temperature of 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.
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 70 ~ 75°C (158 ~ 167°F) to
release the pressure into the atmosphere.
This valve opens at a pressure of 4.0 MPa (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.
Used to detect outdoor air temperature, correct discharge pipe temperature, and for other
purposes.
Used to detect discharge pipe temperature, make the temperature protection control of
compressor, and for other purposes.
Used to detect suction pipe temperature, keep the suction superheated degree constant in
heating operation, and for other purposes.
Used to detect liquid pipe temperature of air heat exchanger, determine defrost operation,
and for other purposes.
Used to the calculation of an internal temperature of compressor, etc.
Used to detect refrigerant overcharge in check operation, and for other purposes.
• Used for outdoor fan speed control.
• Used for inverter radiation fin temperature control.
Refrigerant Circuit
Function
10