Refrigerant Circuit; Rxyq8M, 10M - Daikin VRV II RXYQ8MY1K Service Manual

Refrigerant Circuit

1.

Refrigerant Circuit

1.1

RXYQ8M, 10M

No. in
refrigerant
Symbol
system
diagram
A M1C Inverter compressor (INV)
Standard compressor 1
B M2C
(STD1)
D M1F Inverter fan
Electronic expansion valve
E Y1E
(Main: EV1)
Electronic expansion valve
F Y2E
(Subcool: EV2)
Solenoid valve (Hot gas:
G Y1S
SVP)
Solenoid valve (Receiver
J Y2S
gas discharging: SVG)
Solenoid valve (Non-
L Y3S operating unit liquid pipe
closing: SVSL)
M Y4S 4-way valve
S1NP
N High pressure sensor
H
S1NP
O Low pressure sensor
L
HP pressure switch (For
P S1PH
INV compressor)
S2PH HP pressure switch (For
Q
STD compressor 1)
S — Fusible plug
Pressure regulating valve
U —
2 (Liquid pipe to receiver)
V — Piping heat exchanger
W — Capillary tube
X — Capillary tube
Y — Capillary tube
Thermistor (Outdoor air:
1 R1T
Ta)
Thermistor (Suction pipe:
2 R2T
Ts)
R31T Thermistor (INV discharge
3
pipe: Tdi)
Thermistor (STD1
4 R32T
discharge pipe: Tds1)
Thermistor (Heat
6 R4T
exchanger deicer: Tb)
Thermistor (Subcooling
7 R5T heat exchanger gas pipe:
Tsh)
Thermistor (Receiver
8 R6T
outlet liquid pipe: Tl)
44
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.
RXYQ8, 10M: 37 steps
Since the system is of air heat exchanging type, the fan is operated at 9-step
rotation speed by using the inverter.
While in heating operation, PI control is applied to keep the outlet
superheated degree of air heat exchanger constant.
PI control is applied to keep the outlet superheated degree of subcooling
heat exchanger constant.
Used to prevent the low pressure from transient falling.
Used to collect refrigerant to receiver.
Used to prevent the accumulation of refrigerant in non-operating outdoor
units in the case of multi-outdoor unit system.
Used to switch the operation mode between cooling and heating.
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 4.0 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 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 heat the gas refrigerant from the liquid receiver.
Used to return the refrigerating oil separated through the oil separator to the
INV compressor.
Used to return the refrigerating oil separated through the oil separator to the
STD1 compressor.
Used to add the refrigerant flow capacity to Y1E.
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 subcooling
heat exchanger, keep the superheated degree at the outlet of subcooling
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.
Major Function
Si39-502A
Refirgerant Circuit