Large easy-to-read display. On-demand backlighting makes it easy to read the display in a dark room or hallway. No batteries required. The temperature setting is held permanently in memory in the event of a power failure. Powered through heating-cooling system controls. Easy installation set up and 5-minute compressor bypass saves time and increases installer productivity. Easily configurable by the use of DIP switches. F or C temperature display. Selectable heating cycle rates (1 3 6 9 cph) for a variety of applications. The T8775A Thermostat provides 24V control of heating only systems.