Abstract: In a multizone air conditioning system, a controlled leakage of refrigerant is provided from the high pressure side of the system to an inactive fan coil circuit to raise the pressure therein, such that when that circuit is later brought into an active state, the flow rate of refrigerant suddenly entering the circuit, and the resultant noise, is reduced. In one embodiment the controlled leakage is provided by an orifice formed between the high and low pressure sides of a valve, while in another it is provided by capillary tubes interconnected between active and inactive fan coil circuits.

Abstract: A combination refrigeration circuit and hot water preheater is disclosed. Specific temperature sensing arrangements in combination with a bypass circuit and a continually operating pump are disclosed to obtain effective control of the hot water preheating system in combination with a refrigeration circuit. Additionally disclosed is an air conditioning system having a combination desuperheater hot water preheater built into a compressor section thereof to eliminate field connections to a hot water preheater.