Oil Return Operation - Daikin VRV III REYQ8PY1 Service Manual

Special Control
3.3

Oil Return Operation

This function is used to recover refrigerant oil that flows out from the compressor to the system side by conducting oil
return operation in order to prevent the compressor from running out of refrigerant oil.
3.3.1 Cooling Oil Return Operation
[Start conditions]
Referring to the following conditions, start cooling oil return operation.
• Integral oil rise rate is reached to specified level.
OR • When cumulative compressor operating time exceeds 8 hours (2 hours when the power supply turns ON for
the first time)
Furthermore, the integral oil rise rate is calculated by Tc, Te, and compressor loads.
The higher the compressor operating step No., the cumulative refrigerant oil consumption increases.
Outdoor unit actuator
Compressor 1
Compressor 2
Compressor 3
Outdoor unit fan 1
Outdoor unit fan 2
Four way valve (for heat
exchanger selection)
Four way valve (for high-
and low-pressure gas
pipe selection)
Electronic expansion
valve (main)
Electronic expansion
valve (subcooling)
Electronic expansion
valve (refilling refrigerant) EVJ
Solenoid valve (main
bypass)
Solenoid valve (hot gas)
Solenoid valve (liquid
pipe of refrigerant
regulator)
Solenoid valve (gas
discharge pipe of
refrigerant regulator)
Solenoid valve (drain pipe
of refrigerant regulator)
Solenoid valve (discharge
pipe of refrigerant
regulator)
End conditions
*1: In case of multi outdoor unit system:
Master unit: It conducts the operation listed in the table above.
Slave units: Operating units conduct the operation listed in the table above.
Non-operating units conduct the operation listed in the table above after the "Oil returning" process.
(Non-operating units stop while in "Preparation" mode.)
114
Elect. symbol
Symbol
REYQ REMQ
M1C M1C
— M2C M2C
— M3C
M1F M1F
—
M2F M2F
Y2S
20SA Y3S
Y9S
20SB Y8S Y2S
Y1E
EVM Y1E
Y3E
Y2E
EVT Y3E
Y5E
Y4E Y2E
Y5S
SVE Y6S
Y10S
SVP Y4S Y5S
SVL Y3S Y4S
SVG Y1S Y1S
SVO Y7S Y7S
SVT Y6S Y8S

Oil return operation

52Hz+ON+ON
(Subsequently, constant low
pressure control)
Maintain the number of
compressors that were used
before oil return operation)
Cooling fan control
OFF
ON
1375pls
SH control
80pls
ON
OFF
0pls
0pls
0pls
0pls
• After a lapse of 5 min.
or
• TsA - Te<5°C
Si37-701
Operation after oil return
52Hz+ON+ON
(Subsequently, constant low
pressure control)
Maintain the number of
compressors that were used
before oil return operation)
Cooling fan control
OFF
ON
1375pls
SH control
80pls
ON
OFF
0pls
0pls
0pls
0pls
• After a lapse of 3 min.
• Pe_min<5°C
or
• Pc_max>3.63MPa
• HTdmax>100°C
Function