Special Control
SiBE18-821_C
86
Function
3.4
Pump-down Residual Operation
When activating compressor, if the liquid refrigerant remains in the heat exchanger, the liquid
enters into the compressor and dilutes oil therein resulting in decrease of lubricity.
Therefore, the pump-down residual operation is performed to collect the refrigerant in the heat
exchanger when the compressor is down.
3.4.1 Pump-down Residual Operation in Cooling Operation
3.4.2 Pump-down Residual Operation in Heating Operation
Actuator
Pump-down residual operation
Step 1
Step 2
Compressor
124 Hz Full load
52 Hz Full load
Outdoor fan
Fan control
Fan control
Four way valve (Y1S)
OFF
OFF
Main electronic expansion valve (Y1E)
480 pls
240 pls
Subcooling electronic expansion valve
(Y3E)
0 pls
0 pls
Hot gas bypass valve (Y2S)
OFF
OFF
Ending conditions
2 sec.
2 sec.
Actuator
Pump-down residual operation
Compressor
124 Hz Full load
Outdoor fan
STEP 7
Four way valve (Y1S)
ON
Main electronic expansion valve (Y1E)
0 pls
Subcooling electronic expansion valve
(Y3E)
0 pls
Hot gas bypass valve (Y2S)
OFF
Ending conditions
4 sec.