Refrigerant Circuit - Daikin EWAQ016BAW Service Manual

ESIE11-05

2. Refrigerant Circuit

2.1 Refrigerant Circuit
2.1.1 EWYQ016BA
No. in
refrigerant
Symbol
system
diagram
A M1C Inverter compressor (INV)
D M1F Inverter fan
Electronic expansion valve
E Y1E
(Main: EV1)
Electronic expansion valve
F Y2E
(Subcool: EV2)
G Y1S Solenoid valve (Hot gas: SVP) Used to prevent the low pressure from transient falling.
J Y2S Solenoid valve (Oil return: SVO) Used to return oil from the accumulator to the compressor.
M Y3S Four way valve
N S1NPH High pressure sensor
O S1NPL Low pressure sensor
High pressure switch (For INV
P S1PH
compressor)
Pressure regulating valve
T —
(Liquid pipe)
V — Subcooling heat exchanger
W — Capillary tube
1 R1T Thermistor (Outdoor air: Ta)
2 R2T Thermistor (Suction pipe: Ts)
Thermistor (INV discharge
3 R3T
pipe: Tdi)
Thermistor (Heat exchanger
4 R4T
deicer: Tb)
Thermistor (Subcooling heat
5 R5T
exchanger gas pipe: Tsh)
6 R6T Thermistor (Liquid pipe: Tl)
Thermistor (Accumulator inlet:
7 R7T
Ts1)
General Outline
Name
Inverter compressor is operated on frequencies between 52Hz and 266Hz by using
the inverter, while Standard compressor is operated with commercial power supply
only.
Because the system is an air heat exchange 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 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.
This valve opens at a pressure of 4.0 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 subcool liquid refrigerant from the electronic expansion valve (cooling) or
hydrobox units (heating).
Used to return the refrigerating oil separated through the oil separator to the INV
compressor.
Used to detect outdoor temperature, correct discharge pipe temperature, and others.
Used to detect suction pipe temperature.
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 of gas pipe 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 liquid pipe temperature.
Used to detect gas pipe temperature at the accumulator inlet. Keep the suction
superheated degree constant in heating operation, and others.
Refrigerant Circuit
Major Function
3