Refrigerant Circuit; Reyq8, 10, 12M - Daikin VRV II REYQ8MY1B Service Manual

Refrigerant Circuit

1.

Refrigerant Circuit

1.1

REYQ8, 10, 12M

No. in
refrigerant
Symbol
system
diagram
A M1C Inverter compressor (INV)
B M2C Standard compressor 1(STD1)
D M1F Inverter fan
E Y1E Electronic expansion valve (Main: EV1)
F Y2E Electronic expansion valve (Sub: EV2)
G Y3E Electronic expansion valve (Subcool: EV3)
H Y1S Solenoid valve (Hot gas: SVP)
I Y2S Solenoid valve (Oil equalization: SVO)
Solenoid valve (Receiver gas charging:
J Y3S
SVL)
Solenoid valve (Receiver gas discharging:
K Y4S
SVG)
Solenoid valve (Discharge gas pipe closing:
L Y5S
SVR)
Solenoid valve (Non-operating unit liquid
M Y6S
pipe closing: SVSL)
Solenoid valve (High pressure gas pipe
N Y7S
pressure reduction: SVC)
O Y8S 4-way selector valve (Main: 20S1)
P Y9S 4-way selector valve (Sub: 20S2)
Q S1NPH High pressure sensor
R S2NPL Low pressure sensor
S S1PH HP pressure switch (For INV compressor)
T S2PH HP pressure switch (For STD compressor 1)
V – Fusible plug
Pressure regulating valve 1 (Receiver to
W –
discharge pipe)
Pressure regulating valve 2 (Liquid pipe to
X –
receiver)
Pressure regulating valve 3 (Oil equalizing
Y –
pipe to discharge pipe)
Pressure regulating valve 4 (Discharge to
Z –
discharge pipe)
1 R1T Thermistor (Outdoor air: Ta)
2 R2T Thermistor (Suction pipe: Ts)
3 R31T Thermistor (INV discharge pipe: Tdi)
4 R32T Thermistor (STD1 discharge pipe: Tds1)
6 R4T Thermistor (Heat exchanger deicer: Tb)
Thermistor (Sub-cooling heat exchanger gas
7 R5T
pipe: Tsh)
8 R6T Thermistor (Receiver outlet liquid pipe: Tl)
9 R7T Thermistor (Oil equalizing pipe: To)
Thermistor (Main heat exchanger gas pipe:
10 R81T
Tg1)
Thermistor (Sub heat exchanger gas pipe:
11 R82T
Tg2)
42
Name
Inverter compressor is operated on frequencies between 52 Hz and 210
Hz 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, 12M : 29 steps
Since the system is of air heat exchanging type, the fan is operated at 8-
step rotation speed by using the inverter.
Conducts PI control to make the outlet superheat degree constant when
the air heat exchanger is used at the evaporating side during heating
operation and cooling/heating simultaneous operation.
PI control is applied to keep the outlet superheated degree of sub-
cooling heat exchanger constant.
Used to prevent the low pressure from transient falling.
Used for oil equalizing among outdoor units in multiple-outdoor-unit system.
Used to maintain high pressure while in cooling operation at low outdoor
temperature. And also used to prevent the accumulation of refrigerant in
non-operating outdoor units in the case of multiple-outdoor-unit system.
Used to collect refrigerant to receiver.
Used to make the discharge gas pipe pressure high during heating
operation and cooling/heating simultaneous operation.
Used to prevent the accumulation of refrigerant in non-operating
outdoor units in the case of multiple-outdoor-unit system.
Used to make the discharge gas pipe pressure low during cooling
operation.
Changes the main air heat exchanger into condenser or evaporator.
Changes the sub air heat exchanger into condenser or evaporator.
Used to detect high pressure.
Used to detect low pressure.
In order to prevent the increase of high pressure when a malfunction
occurs, this switch is activated at high pressure of 3.8 MPa 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 to 75°C to release the pressure into the atmosphere.
This valve opens at a pressure of 2 to 2.7 MPa 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 temperature, correct discharge pipe
temperature, and others.
Used to detect suction pipe temperature, keep the suction superheated
degree constant in heating operation, and others.
Used to detect discharge pipe temperature, make the temperature
protection control of compressor, and others.
Used to detect liquid pipe temperature of air heat exchanger, determine
defrosting operation, and others.
Used to detect gas pipe temperature on the evaporation side of sub-
cooling heat exchanger, keep the superheated degree at the outlet of
sub-cooling heat exchanger constant, and others.
Used to detect receiver outlet liquid pipe temperature, prevent the drift
between outdoor units while in heating operation in the case of multiple-
outdoor-unit system, and others.
Used to detect oil equalizing pipe temperature, opening/closing of the oil
equalizing pipe stop valve, and others.
Detects the gas pipe temperature of the main air heat exchanger. Used
for the control making the outlet superheat degree of main air heat
exchanger constant, etc.
Detects the gas pipe temperature of the sub air heat exchanger. Used
for the control making the outlet superheat degree of sub air heat
exchanger constant, etc.
Major Function
Refirgerant Circuit
Si39-306