Specifications

SiUS39-602 Special Control
Function 51
3.2.2 Oil Return Operation in Heating Operation
[Starting conditions]
Start oil return operation in heating operation referring to the following conditions.
Cumulative compressor operating time after power supply turns on exceeds 2 hours and the
time after the completion of previous oil return operation exceeds 8 hours. And cumulative oil
return is calculated based on Tc, Te compressor load.
<In condition of oil return operation>
Compressor cumulative operation time > 8 hours
(However, 2 hours after turning power on first time.)
Actuator
Oil return preparation
operation
Oil return operation Post-oil-return operation
Compressor Upper limit control 124 Hz + ON
1 -st ep in c rea se fr om
(74Hz + OFF) to
(Pc - Pe > 0.4 MPa) time.
Outdoor unit fan
STEP7
or
STEP8
OFF STEP8
Four way valve 1
Depend on previous heat
exchange mode
OFF ON
Four way valve 2
Depend on previous heat
exchange mode
OFF OFF
Main motorized valve (EV1)
Four way valve 1
OFF:1400 pls
ON:SH control
1400 pls 180 pls
Sub motorized valve (EV2)
Four way valve 2
OFF:1400 pls
ON:SH control
1400 pls 1400 pls
Sub-cooling motorized valve (EV3) 0 pls 0 pls 0 pls
Hot gas bypass (SVP) OFF ON ON
Oil equalization valve (SVO) ON ON ON
Receiver gas charging valve (SVL) OFF OFF OFF
Receiver gas discharge valve (SVG) OFF OFF OFF
Discharge gas stop valve (SVR) ON OFF OFF
Non-operating unit liquid pipe stop
valve (SVSL)
ON OFF OFF
High pressure gas pipe pressure
reduction valve (SVC)
OFF ON ON
Ending conditions 2 min.
• 6 min.
• Ts - Te<9
• 160 sec.
• Pc - Pe>58 psi
or
or
Indoor unit actuator Heating oil return operation
Fan
Cooling Thermostat ON unit Set Fan Speed
Heating Thermostat ON unit OFF
Stopping unit OFF
Thermostat OFF unit OFF
Electronic expansion valve
Thermostat ON unit 512 pls
Stopping unit 512 pls
Thermostat OFF unit 512 pls