Daikin REYQ-TA Series, Service Manual

Page: 27 / 324

SiUS371614E Refrigerant Circuit
Refrigerant Circuit 14
1.1.2 REYQ96-168TAYDU, REYQ96-168TATJU
No. in
piping
diagram
Electric
symbol
Name Major function
(1) M1C Inverter compressor
Inverter compressor is operated on frequencies between 52 Hz to 210 Hz by using the
inverter. Compressor operation steps: Refer to page 66~
(2) M2C Inverter compressor
(3) M1F
Inverter fan
Because the system is an air heat exchange type, the fan is operated at 9-step rotation
speed by using the inverter.
(4) M2F
(5) Y1E
Electronic expansion valve
(Heat exchanger upper) While in heating, PI control is applied to keep the outlet superheated degree of air heat
exchanger constant.
(6) Y2E
Electronic expansion valve
(Subcooling heat exchanger) PI control is applied to keep the outlet superheated degree of subcooling heat exchanger
constant.
(7) Y3E
Electronic expansion valve
(Heat exchanger lower) While in heating, PI control is applied to keep the outlet superheated degree of air heat
exchanger constant.
(8) Y4E
Electronic expansion valve
(Receiver gas purge)
Used to collect the refrigerant to receiver.
(9) Y5E
Electronic expansion valve
(Refrigerant cooling) Used to control the refrigerant amount to cool the diode bridge and power module of the
inverter PCB.
(10) Y6E
Electronic expansion valve
(Leak detection)
Used to detect refrigerant leakage.
(11) Y1S
Solenoid valve
(OS oil return 1)
Used to return oil from the oil separator to the compressor (M1C).
(12) Y2S
Solenoid valve
(OS oil return 2)
Used to return oil from the oil separator to the compressor (M2C).
(13) Y3S Solenoid valve (Liquid shutoff) Used to return oil from the accumulator to the compressor.
(14) Y4S Four way valve (HP/LP gas) Used to switch dual pressure gas pipe to high pressure or low pressure.
(15) Y5S
Four way valve
(Heat exchanger lower)
Used to switch outdoor heat exchanger to evaporator or condenser.
(16) Y6S
Four way valve
(Heat exchanger upper)
(17) S1NPH High pressure sensor Used to detect the high pressure.
(18) S1NPL Low pressure sensor Used to detect the low pressure.
(19) S1PH
High pressure switch
(For M1C)
This functions when pressure increases to stop operation and avoid high pressure
increase in the fault operation.
(20) S2PH
High pressure switch
(For M2C)
(21) —
Pressure regulating valve
(Liquid pipe) This is used when pressure increases, to prevent any damage on components caused by
pressure increase in transport or storage.
(22) — Subcooling heat exchanger Apply subcooling to liquid refrigerant.
(23) — Capillary tube
Used to return the refrigerating oil separated through the oil separator to the M1C
compressor.
(24) — Capillary tube
Used to return the refrigerating oil separated through the oil separator to the M2C
compressor.
(25) R1T Thermistor (Outdoor air) Used to detect outdoor air temperature, correct discharge pipe temperature and others.
(26) R21T Thermistor (M1C discharge)
Used to detect discharge pipe temperature.
(27) R22T Thermistor (M2C discharge)
(28) R3T Thermistor (Receiver inlet) Used to detect liquid pipe temperature of receiver inlet.
(29) R4T
Thermistor (Heat exchanger
liquid upper)
This detects temperature of liquid pipe for air heat exchanger.
(30) R5T
Thermistor (Heat exchanger
liquid lower)
(31) R6T Thermistor (Subcooling gas)
Used to detect gas pipe temperature on the evaporating side of subcooling heat
exchanger. Used to exercise the constant control of superheated degree at the outlet of
subcooling heat exchanger.
(32) R7T Thermistor (Subcooling liquid) This detects temperature of liquid pipe for subcooling heat exchanger.
(33) R8T
Thermistor (Heat exchanger
gas upper)
This detects temperature of gas pipe for air heat exchanger.
(34) R9T
Thermistor (Heat exchanger
gas lower)
(35) R10T Thermistor (Suction) Used to detect suction pipe temperature.
(36) R11T Thermistor (Deicer)
Used to detect liquid pipe temperature of air heat exchanger. Used to make judgements
on defrost operation.
(37) R12T
Thermistor (Compressor
suction)
Used to detect suction pipe temperature of compressor.
(38) R13T
Thermistor
(Receiver gas purge)
Used to detect gas pipe temperature of receiver gas purge piping.
(39) R14T Thermistor (M2C body)
Detects compressor surface temperature, this switch is activated at surface temperature
of 120°C (248°F) or more to stop the compressor. (144/168 class models only)
(40) R15T Thermistor (Leak detection) The thermistor detects refrigerant leakage.