Daikin RXSQ24TAVJU, Service Manual

Page: 60 / 311

Special Control SiUS331708EA
47 Functions and Control
3.2 Oil Return Operation
In order to prevent the compressor from running out of oil, oil return operation is conducted to recover oil that has
flowed out from the compressor to the system side.
3.2.1 Oil Return Operation in Cooling
HTdi : Compressor discharge pipe temperature (Tdi) compensated with outdoor air temperature
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Tc : High pressure equivalent saturation temperature
Te : Low pressure equivalent saturation temperature
Ts1 : Suction pipe temperature detected by thermistor R3T (suction pipe 1)
Starting conditions
Referring to the set conditions for the following items, start the oil return operation in cooling.
• Cumulative oil feed rate
• Timer setting (Make this setting so as to start the oil return operation when the initial cumulative operating time
reaches two hours after power supply is turned ON and then every eight hours.)
Furthermore, the cumulative oil feed rate is computed from Tc, Te, and compressor loads.
Outdoor unit
actuator
Electric symbol
Oil return preparation
operation
Oil return operation After oil return operation
24/36 class 48 class 60 class
Compressor M1C M1C M1C Normal control
Control dependent on the
values of Pc and Pe
(
→
Low pressure
protection control)
Normal control from current
rps
Outdoor fan M1F M1F
M1F,
M2F
Fan control (Normal
cooling) Fan control (Normal
cooling) Fan control (Normal
cooling)
Four way valve Y1S Y1S Y1S OFF OFF OFF
Main electronic
expansion valve
Y1E Y1E Y1E 480 pulse (Fully open) 480 pulse (Fully open) 480 pulse (Fully open)
Subcooling
electronic
expansion valve
 
Y3E SH control 0 pulse 0 pulse
Hot gas bypass
valve
Y2S
 
OFF OFF OFF
Injection valve Y3S Y3S

OFF OFF OFF
Ending conditions 15 seconds
•
3 minutes
•
Ts1–Te < 3°C
(5.4°F)
•
A lapse of 20
minutes
•
System rps is
large than oil
return rps for
more than 6
minutes.
•
3 minutes
•
Pe < 0.6 MPa (87 psi)
•
HTdi > 1 10°C (230°F)
•
Pc > 3.6 MPa (522 psi)
&
OR
OR
Indoor unit actuator Cooling oil return operation
Indoor fan
Thermostat ON unit Remote controller setting
Non-operating unit OFF
Thermostat OFF unit Remote controller setting
Electronic expansion valve
Thermostat ON unit Normal opening
Non-operating unit 224 pulse
Thermostat OFF unit Normal opening with forced thermostat ON