Patent ID: 7261243

Claim:
A digital thermostat for controlling the operation of a climate control system having at least a heat pump system and an auxiliary heating system, comprising: a display means for visually displaying operating error information to a user of the thermostat; a temperature sensor for sensing the outside ambient temperature; a processor being configured to deactivate the heat pump system in response to the temperature sensor sensing an outside ambient temperature below a predetermined temperature value, and configured to responsively activate the auxiliary heating system, said processor having an input means for receiving at least one communication signal from either the heat pump or auxiliary heating system indicating whether the heat pump or auxiliary heating system is not operating, wherein the processor responds to the non-operating communication signal by initiating the deactivation of the non-operating system and the activation of the other operable system, and where the communication signal is a signal from an auxiliary heating system controller indicating the auxiliary heating system is not operating, the processor responsively initiates the activation of the heat pump system even if the outside ambient temperature is below the predetermined temperature value.