The device has a single liquid circuit for selectively heating or cooling the vehicle chamber and controled valves to regulate the quantity of heat requested for the loads. An electrically controled 3-way valve is arranged in the main forward line for the heat carrying medium only at the point at which the medium cooled by an air conditioning box enters the line. Quantity regulating valves are provided to distribute the requested heat to loads. The device has a single liquid circuit for selectively heating or cooling the vehicle chamber and regulating valves controled by a controler to regulate the quantity of heat requested for the loads. An electrically controled 3-way valve (V2) is arranged in the main forward line (19) for the heat carrying medium only at the point at which the medium cooled by an air conditioning box (12) enters the line. Quantity regulating valves (V3,V4) are provided to distribute the requested heat to loads (15-18).
