Abstract: Methods and circuits for providing auxiliary or remote temperature set or set-back capability in comparator-based thermostatic temperature control systems. In particular, the invention is applicable to thermostatic control systems of the general type including a temperature-responsive source for producing a temperature-dependent voltage as a function of sensed temperature, a reference voltage source for establishing a temperature set point, a voltage comparator having a comparison input and a reference input for producing a control output signal for energizing a thermal conditioning element when voltages applied respectively to the comparison and reference inputs have at least a predetermined relationship with respect to each other, an electrical connection between said temperature-responsive voltage source and the comparison input, and an electrical connection between the reference voltage source and the reference input.

Abstract: A two-stage circuit for controlling all operational functions of a reversible air cycle heat pump unit, including room thermostat functions and defrosting functions. All user controllable functions are controlled via a remotely locatable thermostat-like control unit mounted on an inside wall of the room separate from the heat pump unit, and connected to the heat pump unit with only five conductors. A number of desirable functions and features are provided. For example, for optimum energy usage the control provides two stages in both heating and cooling modes of operation, with almost constant temperature differential between the two stages regardless of temperature setting, and almost constant hysteresis for each stage. To facilitate compliance with Government-imposed regulations where applicable, heating and cooling limits are independently adjustable without any modification whatsoever for use in those public buildings where heating and cooling must be limited.