Abstract: Heat pump/air conditioning converter apparatus for directing a refrigerant from a compressor to a first heat exchanger located within a building and a second heat exchanger located outside the building for selectively cooling and heating the first heat exchanger. The apparatus has a housing within which a reversing valve, a liquid refrigerant flow control valve system, an expansion valve and an accumulator tank is incorporated. The housing has a number of cavities for receiving the various components of the valves and tank, and a number of passageways for directing the refrigerant to the components to minimize the number of external connections. The reversing valve incorporates an axially slideable rod having a large main piston positioned centrally thereon and a pair of smaller valve opening/closing piston members at each end, one end controlling the hot high pressure gaseous refrigerant and the other end controlling the low pressure relatively cool gaseous refrigerant.