Daikin REYQ-TA Series, Service Manual

Page: 31 / 324

SiUS371614E Refrigerant Circuit
Refrigerant Circuit 18
1.3 Outdoor-Air Processing Unit
Note:
∗
1. SH control: Superheated control of heat exchanger outlet
∗
2. SC control: Subcooling control of heat exchanger outlet
No. in
piping
diagram
Electric
symbol
Name Function
(1) Y1E Electronic expansion valve
Used to control the flow rate of refrigerant, and make the
SH control (
∗
1) while in cooling.
(2) Y1S Solenoid valve
Used to bypass hot gas while in heating with thermostat
OFF. Closed while in cooling.
(3) — Capillary tube
Used to reduce pressure from high to low in bypassing hot
gas.
(4) R1T Suction air thermistor Used to turn ON or OFF the thermostat.
(5) R2T Liquid pipe thermistor
Used to control the opening degree of electronic expansion
valve under the SC control (
∗
2).
(6) R3T Gas pipe thermistor
Used to control the opening degree of electronic expansion
valve under the SH control.
(7) R4T Discharge air thermistor
Used to control the electronic expansion valve opening and
thermostat ON/OFF so as to keep the discharge air
temperature at the set temperature.
C: 4D018650D
Heat exchanger
Distributor
Fan
Filter
Filter
Filter
Electronic
expansion valve
Capillary
tube
Solenoid
valve
Check
valve
Gas pipe
connection port
Liquid pipe
connection port
(5)
(7)
(6)
(3)
(2)
(1)
(4)