Daikin VRV III REYQ10PY1B Service Manual Download

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Refrigerant Circuit

SiBE37-701

Refrigerant Circuit

1.5

REMQ14P, 16P (Multi 14, 16HP)

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.
Compressor operation steps : Refer to page 104~107.

M2C

Standard compressor 1 (STD1)

M3C

Standard compressor 2 (STD2)

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.

Y1E

Electronic expansion valve
(Main: EVM)

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

Y3E

Electronic expansion valve
(Subcool: EVT)

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

Y2E

Electronic expansion valve
(Refrigerant charge EVJ)

This is used to open/close refrigerant charge port.

Y6S

Solenoid valve (Main bypass SVE)

This opens in cooling operation.

Y5S

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

Y4S

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.

Y8S

Solenoid valve (Discharge
pipe of refrigerant regulator)

Bypass the high pressure gas to the refrigerant regulator.

Y3S

4 way valve (Heat exchanger
switch 20SA)

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

Y2S

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
compressor)

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

S2PH

HP pressure switch (For STD
compressor 1)

S3PH

HP pressure switch (For STD
compressor 2)

—

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

Used to return the refrigerating oil separated through the oil separator to the STD2 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.

R8T

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)

R33T

Thermistor (STD2 discharge pipe: Tds2)

R4T

Thermistor (Heat exchanger
deicer: Tb)

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

R2T

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.

R7T

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.

R5T

Thermistor (Subcooling heat
exchanger gas pipe: Tsh)

This detects temperature of gas pipe on the evaporator side for the 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.

R9T

Thermistor (Liquid pipe Tsc)

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