Special Control
3.3 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.
3.3.1 Pump-down Residual Operation in Heating Operation [R-410A]
Actuator
Compressor
Outdoor unit fan
Four way valve
Main electronic expansion valve (EV1)
Subcooling electronic expansion valve
(EV3)
Hot gas bypass valve (SVP)
Ending conditions
54
Pump-down residual operation
124 Hz Full load
STEP7
ON
0 pls
0 pls
OFF
4 sec.
ESIE09-08
Function