SiBE28-805 Special ControlFunction 433.4 Pump-down Residual Operation3.4.1 Pump-down Residual Operation in Cooling OperationIf the liquid refrigerant stays in the Evaporator at the startup of a compressor, this liquid refrigerant enters thecompressor, thus resulting in diluted oil in the compressor and then degraded lubrication performance.Consequently, in order to recover the refrigerant in the Evaporator while the compressor stops, the pump-down residualoperation is conducted.3.4.2 Pump-down Residual Operation in Heating OperationActuator Master unit operation Slave unit operationCompressor 124 Hz OFFOutdoor unit fan Fan control OFFFour way valve OFF OFFMain motorized valve (EV1) 480 pls 0 plsSubcooling motorized valve (EV2) 0 pls 0 plsHot gas bypass valve (SVP) OFF OFFAccumulator oil return valve (SVO) ON ONEnding conditions • 5 min.orActuator Master unit operation Slave unit operationCompressor 124 Hz OFFOutdoor unit fan STEP7 STEP4Four way valve ON ONMain motorized valve (EV1) 0 pls 0 plsSubcooling motorized valve (EV2) 0 pls 0 plsHot gas bypass valve (SVP) OFF OFFAccumulator oil return valve (SVO) ON ONEnding conditions • 3 min.or
