LOW VOLTAGE WALL MOUNTED THERMOSTATS Universal Thermostat (UT Series) ? Heat Only for 24V and Millivolt Systems Allows vertical or horizontal mounting. Wall mount thermostats provide low voltage operation and feature Fahrenheit/Celsius temperature scales. Gas, oil or electric heat operation. Thermostats do not contain mercury. No leveling required. 1 amp. 50-90° F temperature range. UL listed.