Defying the Laws of Gravity. Condenser drainage. The video shows a liquid receiver installed 20 feet above the outdoor condenser. The study and behaviour of liquid refrigerant flowing from an air-cooled condenser into a liquid receiver has been provided. A liquid receiver and LPA® pump was lifted to roof top to simulate a 20′ condenser drain rise.  The improved condenser flow is a side effect of a phenoemon occuring in the liquid receiver. We refer to that phenoemon as “back pressure”.  In a new patent application, the same “back pressure” eliminates pump cavitation at any NPSH. A similar method is applied to pumped Co2 recirculation refrigeration circuits.  —-> YouTube