Patent ID: 7156317

Claim:
A programmable thermostat having an additional fan recirculate function, comprising: a fan switch including fan on, fan auto and fan recirculate positions, a cool-heat switch, a microprocessor for controlling heat-cool cycles and fan cycles in response to upper and lower temperature values, means for connecting the fan to a power source in response to the fan switch being in the fan on position, said microprocessor controlling the fan cycle when the fan switch is in the fan recirculate position including determining when the heat-cool cycles have been off for a predetermined period and in response thereto initiating a fan cycle for a predetermined fixed, non-adjustable time that may be terminated by the heat-cool cycles, said microprocessor having a resettable timer and means for reading the timer to determine when the heat-cool cycle predetermined off period has expired and in response thereto initiates a fixed fan cycle and after the fan cycle is complete resets the resettable timer to zero.