Service manual

SiUS28-902_a Special Control
Function 22
3.2 Oil Return Operation
Oil discharged by the compressor to the field piping is collected by the oil return operation.
3.2.1 Oil Return Operation in Cooling Operation
[Conditions to start]
The cooling oil-returning operation is started under the following conditions:
 Integrated amount of displaced oil
 Timer
After the power is turned on, integrated operatingtime is 2 hours and subsequently every 8
hours.)
In addition, the integrated amount of displaced oil is derived from Tc, Te, and the
compressor load.
Outdoor unit actuator
Oil return preparation
operation
Oil return operation Postoil-return operation
Compressor Upper limit control 124 Hz 124 Hz
Outdoor unit fan Fan control Fan control Fan control
Four-way valve OFF OFF OFF
Main electronic expansion valve
(EV1)
1400 pls 1400 pls 1400 pls
Subcooling electronic expansion
valve (EV2)
SH control 0 pls 0 pls
Hot gas bypass valve (SVP) OFF ON ON
Receiver gas discharging valve
(SVG)
OFF OFF OFF
Ending conditions 20 sec.
• 6 min.
• Ts - Te<5
3 min.
or
Indoor unit actuator Cooling oil return operation
Fan
Thermostat ON unit Set Air Volume
Stopping unit OFF
Thermostat OFF unit OFF
Electronic expansion valve
Thermostat ON unit Normal opening
Stopping unit 200 pls
Thermostat OFF unit 200 pls