TX-128 underfloor heating thermostat LED indicative lamp is light when heating is on ·On/off control output for heating ·Manual switch and knob, easy to operate ·Energy-saving mode,connect with programmable timer ·External or internal temperature sensor is optional ·When double sensor is used, internal sensor with control temperature while external sensor with limit temperature ·Sensor protection function from no heating when short or off circuit. ·Heating contact is off when room temperature is lower than selected setting temperature