Oil Return Operation - Daikin VRV II RXYQ8MY1K Service Manual

Si39-502A
3.2

Oil Return Operation

In order to prevent the compressor from running out of oil, the oil return operation is conducted to recover oil flown out
from the compressor to the system side.
3.2.1 Oil Return Operation in Cooling Operation
[Start 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
Compressor
Outdoor unit fan
Four way valve
Main motorized valve (EV1)
Subcooling motorized valve (EV2)
Hot gas bypass valve (SVP)
Receiver gas discharging valve
(SVG)
Non-operating unit liquid pipe stop
valve (SVSL)
Ending conditions
∗ In the case of multi-outdoor-unit system,
Master unit: Performs the operations listed in the table above.
Slave units: Operating units perform the operations listed in the table above.
Non-operating units perform the operations listed in the table above from the oil return operation.
(Non-operating unit stops during "oil return preparation operation".)
Fan
Electronic expansion valve
Function
Oil return preparation
operation
Upper limit control
Fan control
OFF
2000 pls
SH control
OFF
OFF
ON
20 sec.
Indoor unit actuator
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Thermostat ON unit
Stopping unit
Thermostat OFF unit

Oil return operation

177 Hz + OFF + OFF
Lapse of 20 sec.
Pe<5.5k⇒Inv 25 Step Down
Pe>6.5k⇒1 Step Up
Fan control
OFF
2000 pls
0 pls
ON
OFF
ON
• 3 min.
or
• Ts - Te<5°C
Cooling oil return operation
Set flow rate (subject to the situation)
Normal opening
Special Control
Post-oil-return operation
52 Hz + OFF + OFF
Fan control
OFF
2000 pls
0 pls
ON
OFF
ON
• 3 min.
• Pe<0.4MPa
or
• HTdi>110°C
OFF
OFF
200 pls
200 pls
61