Abstract: A thermostat includes a display and an illumination device that is configurable to illuminate the display in a partial illumination mode and a full illumination mode. In the partial illumination mode the illumination device generates a light intensity sufficient to review the settings of the thermostat without generating heat of a sufficient amount to disrupt thermostat measurements. The full illuminated condition is actuated upon interaction with the thermostat. Once interaction with the thermostat is completed the illumination device thermostat returns to the partially illuminated condition.

Abstract: A HVAC system provides a central control which detects failed stage(s); removes the failed stage(s) from the staging sequence used by the controller; and later checks the failed stage periodically to see if the failed stage has become functional so that the no properly operational stage is returned to a staging sequence. The central control detects the failed stages and/or components by direct communication with the failed stages and/or components and/or by monitoring a temperature of a controlled area to determine if any particular stage is operating properly.

Abstract: A control for controlling a multi-zone HVAC system, wherein the heating or cooling equipment is operable in multiple stages, takes the demand on the system over time into account when determining an appropriate stage. In particular, a time integral of the system demands is utilized along with a current system demand to determine an appropriate stage. In this manner, a weakness in the prior art of allowing a long-term, small difference between the desired set point and the actual temperature in the various zones is addressed.