DE3127957

A refrigeration circuit is disclosed which is operable in each of four distinct modes for the heating or cooling of a space, the production of a heated liquid, or the simultaneous cooling of a space and production of heated liquid. The circuit includes compressor means; indoor, outdoor, and liquid heat exchange means; along with vapor conduit means including first valve means and liquid conduit means including second valve means so as to afford selective operation of the circuit in any one of the aforementioned modes. A significant feature of the invention lies in the fact that, during operation in any particular mode, the inactive heat exchange means of the circuit is vented to the suction side of the compressor means so as to afford proper refrigerant charge control within the circuit. Control means are further disclosed which sense the load imposed upon the compressor means and prevent overloading thereof during operation in a water heating mode.