Daikin VRV III REYQ8PY1, Service Manual

Page: 125 / 452

Special Control Si37-701
114 Function
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.
• 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.
*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.)
Outdoor unit actuator Symbol
Elect. symbol
Oil return operation Operation after oil return
REYQ REMQ
Compressor 1
—
M1C M1C
52Hz+ON+ON
(Subsequently, constant low
pressure control)
Maintain the number of
compressors that were used
before oil return operation) 52Hz+ON+ON
(Subsequently, constant low
pressure control)
Maintain the number of
compressors that were used
before oil return operation)
Compressor 2 M2C M2C
Compressor 3 — M3C
Outdoor unit fan 1
—
M1F M1F
Cooling fan control Cooling fan control
Outdoor unit fan 2 M2F M2F
Four way valve (for heat
exchanger selection)
20SA
Y2S
Y9S
Y3S OFF OFF
Four way valve (for high-
and low-pressure gas
pipe selection)
20SB Y8S Y2S ON ON
Electronic expansion
valve (main)
EVM
Y1E
Y3E
Y1E 1375pls 1375pls
Electronic expansion
valve (subcooling)
EVT
Y2E
Y5E
Y3E SH control SH control
Electronic expansion
valve (refilling refrigerant)
EVJ Y4E Y2E 80pls 80pls
Solenoid valve (main
bypass)
SVE
Y5S
Y10S
Y6S ON ON
Solenoid valve (hot gas) SVP Y4S Y5S OFF OFF
Solenoid valve (liquid
pipe of refrigerant
regulator)
SVL Y3S Y4S 0pls 0pls
Solenoid valve (gas
discharge pipe of
refrigerant regulator)
SVG Y1S Y1S 0pls 0pls
Solenoid valve (drain pipe
of refrigerant regulator)
SVO Y7S Y7S 0pls 0pls
Solenoid valve (discharge
pipe of refrigerant
regulator)
SVT Y6S Y8S 0pls 0pls
End conditions
•
After a lapse of 5 min.
•
TsA - Te<5
°
C
•
After a lapse of 3 min.
•
Pe_min<5
°
C
•
Pc_max>3.63MPa
•
HTdmax>100
°
C
OR
or
or