Tekmar tN4 Thermostat- Comm. Touch (heat/cool/humidity). tekmarNet??rmostat 553 is a communicating touchscreen rmostat designed to operate two heating stages, one cooling stage, a fan and relative humidity. heating stages can be hydronic, forced air or a single stage heat pump. cooling stage is eir an air conditioner or heat pump. re are two auxiliary sensor inputs available to measure room, floor, outdoor, coil or duct temperature. optional floor sensor allows precise heating of radiant floors by controlling floor temperature and maintaining desired room air temperature. Relative humidity level can be measured and controlled using built-in humidity sensor. large touchscreen allows you to easily adjust 7-day programmable schedules and room temperature to optimize comfort and energy savings. 553 can connect to tekmarNet??controls using two or four wires or it can operate as a stand-alone device.