Check the listing for details. Tekmar 553 Thermostat. Color: White, Condition: Used. Listed at 235.00 USD. Tekmar 553 Thermostat. The tekmarNet Thermostat 553 is a communicating touchscreen thermostat designed to operate two heating stages, one cooling stage, a fan and relative humidity. The heating stages can be hydronic, forced air or a single stage heat pump. The cooling stage is either an air conditioner or heat pump. There are two auxiliary sensor inputs available to measure room, floor, outdoor, coil or duct temperature. The optional floor sensor allows precise heating of radiant floors by controlling the floor temperature and maintaining the desired room air temperature. Relative humidity level can be measured and controlled using the built-in humidity sensor. The large touchscreen allows you to easily adjust 7-day programmable schedules and room temperature to optimize comfort and energy savings. The 553 can connect to tekmarNet controls using two or four wires or it can operate as a stand-alone device. Features: Optimum start, scenes - Warm weather shut down - Zone synchronization - Auto heating cycle - tekmarNet communication compatible - Radiant floor heating and cooling - Outdoor and floor temperature display - Touchscreen technology - 2 auxiliary sensor inputs - Daylight savings time - Backlight - Temporary hold - Away scene key - Air group master or member - Network schedule master or member - Zone post purge - Programmable schedule Used for 2 months in a system and replaced with a different style thermostat. All units are fully functional.