Daikin VRV III REYQ10PY1 Service Manual Download

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Refrigerant Circuit

Si37-701

Refrigerant Circuit

Refrigerant Circuit

1.1

REYQ8P, 10P, 12P

No. in

refrigerant

system

diagram

Symbol

Name

Major Function

M1C

Inverter compressor (INV)

Inverter compressor is operated on frequencies between 52Hz and 210Hz by using
the inverter, while Standard compressor is operated with commercial power supply
only. The number of operating steps is as follows when Inverter compressor is
operated in combination with Standard compressor.
REYQ8, 10, 12P : 37 steps

M2C

Standard compressor 1
(STD1)

M1F

Inverter fan

Since the system is of air heat exchanging type, the fan is operated at 9-step rotation
speed by using the inverter.

M2F

Inverter fan

Since the system is of air heat exchanging type, the fan is operated at 9-step rotation
speed by using the inverter.

5(6)

Y1E

(Y3E)

Electronic expansion valve
(Main1 (Main2))

While in heating operation, PI control is applied to keep the outlet superheated degree
of air heat exchanger constant.

7(8)

Y2E

(Y5E)

Electronic expansion valve
(Subcool1 (Subcool2))

PI control is applied to keep the outlet superheated degree of subcooling heat
exchanger constant.

Y4E

Electronic expansion valve
(Refrigerant charge EVJ)

This is used to open/close refrigerant charge port.

10(11)

Y5S

(Y10S)

Solenoid valve (Main bypass1
(Main bypass2))

This opens in cooling operation.

Y4S

Solenoid valve (Hot gas: SVP) Used to prevent the low pressure from transient falling.

Y3S

Solenoid valve (Refrigerant
regulator liquid pipe SVL)

This is used to collect refrigerant to the refrigerant regulator.

Y1S

Solenoid valve (Refrigerant
regulator gas purging pipe
SVG)

This is used to collect refrigerant to the refrigerant regulator.

Y7S

Solenoid valve (Refrigerant
regulator discharge pipe SVO)

This is used to discharge refrigerant from the refrigerant regulator.

Y6S

Solenoid valve (Discharge
pipe of refrigerant regulator)

Bypass the high pressure gas to the refrigerant regulator.

17(18)

Y2S

(Y9S)

4 way valve (Heat exchanger
switch 20SA)

This is used to switch outdoor heat exchanger to evaporator or condenser.

Y8S

4 way valve (Dual pressure
gas pipe switch 20SB)

This is used to switch dual pressure gas pipe to high pressure or low pressure.

S1NPH High pressure sensor

Used to detect high pressure.

S2NPL Low pressure sensor

Used to detect low pressure.

S1PH

HP pressure switch (For INV)

This functions when pressure increases to stop operation and avoid high pressure
increase in the fault operation.

S2PH

HP pressure switch (For STD)

—

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.

—

Pressure regulating valve
(Refrigerant regulator)

This is used when pressure increases, to prevent any damage on components caused
by pressure increase in transport or storage.

—

Subcooling heat exchanger

Apply subcooling to liquid refrigerant.

—

Refrigerant regulator

Surplus refrigerant is held according to the operation conditions.

—

Capillary tube

Used to return the refrigerating oil separated through the oil separator to the INV compressor.

—

Capillary tube

Used to return the refrigerating oil separated through the oil separator to the STD1
compressor.

—

Capillary tube

This is used to discharge refrigerant from the refrigerant regulator.

R1T

Thermistor (Outdoor air: Ta)

Used to detect outdoor temperature, correct discharge pipe temperature, and others.

32(42)

R8T

(R10T)

Thermistor (Suction pipe: TsA) Used to detect suction pipe temperature.

R31T

Thermistor (INV discharge
pipe: Tdi)

Used to detect discharge pipe temperature. Used for compressor temperature
protection control.

R32T

Thermistor (STD1 discharge
pipe: Tds1)

35(45)

R4T

(R12T)

Thermistor (Heat exchanger
deicer: Tb)

Used to detect liquid pipe temperature of air heat exchanger. Used to make judgments
on defrosting operation.

36(46)

R2T

(R11T)

Thermistor (Heat exchanger
gas pipe Tg)

This detects temperature of gas pipe for air heat exchanger. Used to exercise the
constant control of superheated degree when an evaporator is used for outdoor unit
heat exchanging.

37(47)

R7T

(R15T)

Thermistor (Heat exchanger
liquid pipe Tf)

This detects temperature of liquid pipe between the air heat exchanger and main
electronic expansion valve. Used to make judgments on the recover or discharge
refrigerants to the refrigerant regulator.

38(48)

R5T

(R13T)

Thermistor (Subcooling heat
exchanger gas pipe: Tsh)

Used to detect gas pipe temperature on the evaporation side of subcooling heat
exchanger. Used to exercise the constant control of superheated degree at the outlet
of supercooled heat exchanger.

R6T

Thermistor (Subcooling heat
exchanger liquid pipe Tl)

This detects temperature of liquid pipe between the main expansion valve and
subcooling heat exchanger.

40(50)

R9T

(R14T)

Thermistor (Liquid pipe Tsc)

This detects temperature of liquid pipe between the liquid stop valve and subcooling
heat exchanger.