The principal object of the digital thermostat is to provide an improved energy conserving thermostatic control which utilizes digital control circuits for regulating the operation of heating or air conditioning systems.

Another object of the invention is to provide a fan coil unit control which will automatically regulate the temperature of a home or office at a selected night temperature and at a selected day temperature during predetermined times of night and day, respectively.

Yet another object of the zone valve is to provide such a digital thermostatic control which can be used for automatically regulating the temperature of the controlled area at either a comfort temperature level or an energy conservation level in combination with both heating and air conditioning systems.