Special Control
SiUS331604E
39
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
flown 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
Pe : Low pressure sensor detection value
Tc : High pressure equivalent saturation temperature
Te : Low pressure equivalent saturation temperature
Ts : Suction pipe temperature detected by thermistor
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
RXTQ36
TAVJU
RXTQ48
TAVJU
RXTQ60
TAVJU
Compressor
M1C
M1C
M1C
Take the current step as
the upper limit.
Minimum frequency
(
→
Low pressure
protection control)
Same as oil return
operation.
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
Ending conditions
20 seconds
•
3 minutes
•
Ts – Te < 5
°
C (9
°
F)
•
3 minutes
•
Pe < 0.6 MPa (87 psi)
•
HTdi > 1
10°C (230°F)
OR
OR
Indoor unit actuator
Cooling oil return operation
Indoor fan
Thermostat ON unit
Remote controller setting
Stopping unit
OFF
Thermostat OFF unit
Remote controller setting
Electronic expansion valve
Thermostat ON unit
Normal opening
Stopping unit
224 pulse
Thermostat OFF unit
Normal opening with forced thermostat ON
Summary of Contents for VRV IV-S RXTQ-TAVJU Series
Page 1: ...Service Manual SiUS331604E RXTQ36 48 60TAVJU Heat Pump 60 Hz...
Page 254: ...Wiring Diagrams SiUS331604E 241 Appendix RXTQ48TAVJU 3D100496A...
Page 255: ...SiUS331604E Wiring Diagrams Appendix 242 RXTQ60TAVJU 3D100497A...
Page 260: ...Wiring Diagrams SiUS331604E 247 Appendix FXEQ07 09 12 15 18 24PVJU C 3D098557...
Page 267: ...SiUS331604E Wiring Diagrams Appendix 254 FXTQ12 18 24 30 36 42 48 54PAVJU 3D065036G...
Page 270: ...Wiring Diagrams SiUS331604E 257 Appendix VAM1200GVJU 3D073270C...
Page 271: ...Revision History Month Year Version Revised contents 06 2016 SiUS331604E First edition...