Daikin VRV RXYQ72-384XAYCA, Service Manual

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Refrigerant Circuit (Piping Diagrams) SiUS342004EB
33 Part 2 Refrigerant Circuit
1. Refrigerant Circuit (Piping Diagrams)
1.1 Outdoor Unit
No. in
piping
diagram
Electric
symbol
Name Function
(1) M1C
Compressor Compressor is operated in multi-steps according to Te and Tc by using
inverter.
(2)
M1F
M2F
Fan motor Because the system is an air heat exchange type, the fan rotation speed is
varied by using inverter.
(3) Y1E
Electronic expansion valve
(Heat exchanger upper)
While in heating, PI control is applied to keep the outlet superheating degree
of air heat exchanger constant.
(4) Y2E
Electronic expansion valve
(Subcooling heat exchanger)
PI control is applied to keep the outlet superheating degree of subcooling heat
exchanger constant.
(5) Y3E
Electronic expansion valve
(Heat exchanger lower)
While in heating, PI control is applied to keep the outlet superheating degree
of air heat exchanger constant.
(6) Y4E
Electronic expansion valve
(Subcooling injection)
Used to control compressor injection.
(7) Y5E
Electronic expansion valve
(Refrigerant cooling)
Used to control the refrigerant amount to cool the diode bridge and power
module of the inverter PCB.
(8) Y7E
Electronic expansion valve
(Receiver gas purge)
Used to collect the refrigerant to receiver.
(9) Y1S
Solenoid valve
(Oil separator oil return)
Used to return oil from the oil separator to the compressor.
(10) Y2S Solenoid valve (Hot gas bypass) Used to flow discharge gas to the compressor inlet.
(11) Y3S Solenoid valve (Liquid shutoff) Used to shut off liquid refrigerant flow to the receiver.
(12) Y4S
Four way valve (HP/LP gas
pipe)
Used to switch dual pressure gas pipe to high pressure or low pressure.
(13) Y5S
Four way valve
(Heat exchanger lower)
Used to switch outdoor heat exchanger to evaporator or condenser.
(14) Y6S
Four way valve
(Heat exchanger upper)
(15) Y7S
Solenoid valve
(Accumulator oil return)
Used to return oil from the accumulator to the compressor.
(16) S1NPH High pressure sensor Used to detect the high pressure.
(17) S1NPL Low pressure sensor Used to detect the low pressure.
(18) S1PH High pressure switch (For
compressor)
This functions when pressure increases to stop operation and avoid high
pressure increase in the fault operation.
(19) —
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.
(20) — Subcooling heat exchanger Apply subcooling to liquid refrigerant.
(21) —
Capillary tube Used to return the refrigerating oil separated through the oil separator to the
compressor.
(22) R1T
Thermistor (Outdoor air) Used to detect outdoor air temperature, correct discharge pipe temperature
and others.
(23) R21T Thermistor (M1C discharge) Used to detect discharge pipe temperature.
(24) R3T Thermistor (Receiver inlet) Used to detect liquid pipe temperature of receiver inlet.
(25) R4T
Thermistor
(Heat exchanger liquid upper)
This detects temperature of liquid pipe for air heat exchanger.
(26) R5T
Thermistor
(Heat exchanger liquid lower)
(27) R6T Thermistor (Subcooling gas) This detects temperature of gas pipe for subcooling heat exchanger.
(28) R7T Thermistor (Subcooling liquid) This detects temperature of liquid pipe for subcooling heat exchanger.
(29) R8T
Thermistor
(Heat exchanger gas upper)
This detects temperature of gas pipe for air heat exchanger.
(30) R9T
Thermistor
(Heat exchanger gas lower)
(31) R10T Thermistor (Suction) Used to detect suction pipe temperature.
(32) R11T Thermistor (Deicer)
Used to detect liquid pipe temperature of air heat exchanger. Used to make
judgements on defrost operation.