Heating and cooling system for a multiple coil installation

Claim 1

A heating and cooling system for supplying hot or cold water to a multiple coil installation comprising a heating circuit, a cooling circuit and a bypass circuit, said heating circuit including, a water reservoir, a temperature sensing control and a first pump, said cooling circuit including said water reservoir, a temperature sensing control and a second pump, a first conduit intersecting said heating and cooling circuits and extending to the inlet side of the multiple coil installation, a second conduit connecting the outlet side of the multiple coil unit with said reservoir, said bypass circuit including a third conduit connecting said first and second conduits, a check valve in said third circuit, and a third pump in said first conduit downstream of the intersection of said first and third conduits, said third pump being continuously energized when the system is in a heating or cooling mode, and control means for energizing said first pump or said second pump to circulate hot or cold water through said heating or cooling circuit respectively, one of said first or second pumps being energized and the other one of said first or second pump being energized depending on whether the system is in the heating mode or cooling mode, said check valve being closed in said third conduit while said first pump or said second pump is energized, and remaining closed until the temperature sensing control of the heating or cooling circuit shuts off the corresponding first or second pump after which time said check valve opens, whereby the water from the multiple coil installation is circulated by said third pump in a closed path through said bypass circuit, said conduits and the multiple coil installation, thus bypassing said heating and cooling circuits, said first and second pumps both being deenergized when said bypass circuit is opened.