usually be installed on the inlet of condenser), which can regulate the flow of cooling water according to the change of condensing pressure. When discharge pressure (condensing pressure) of compressor rises, valve is turned up automatically, so more cooling water enters the condenser to accelerate the condensing of refrigerant. Reversely, when discharge pressure (condensing pressure) of compressor drops, valve is turned down automatically, so cooling water reduces and the condensing pressure is kept within certain range.