D-28F digital hydronic radiant floor heating thermostat is specifically designed for Radiant Floor Heating Systems. It is so flexible that it can be used to control either air temperature (A Mode) or floor temperature (F Mode) or a combination of air temperature with floor temperature limits(AF Mode). An auxiliary remote sensor is provided to measure slab temperature in order to control the floor temperature within desired maximum and minimum limits. FEATURES: Large LCD display Battery operated Freeze protection Contains NO Mercury, environmentally safe Two wire type thermostat Selectable display in °F or °C EEPROM for setting backup Supplied with 10ft. floor sensor Easy Comfort or Economy Setpoint Selection buttons SPECIFICATIONS: Display Format: Liquid Crystal Display(LCD) Power Input : Battery 1.5 VDC AA x 2 with Battery-Low indicator & protection Selectable display in °F or °C Temperature control range: Room: 40-95°F(5-35°C) Floor Temperature Control Range: 40-113°F(5-45°C) Temperature Display Range: 14-122°F(-10-50°C) with accuracy ± 0.2°F(0.1°C). Note: No decimal indicator above 100°F Maximum Floor Temperature Limit.(F & AF Mode): 68-113°F(20-45°C) Default: 85°F(29°C) Minimum Floor Temperature Limit(F Mode only): 40-68°F(5-20°C) Default: 59°F(15°C). Note: In AF Mode, only Maximum Limit is available Contact Rating: 10A Floor limits switching differential: 4°F(2°C). Factory Preset (not user adjustable) Freeze protection: factory preset. In effect when thermostat is OFF by Power Button. A & AF Mode 40°F(5°C). F Mode: 50°F(10°C) Short Cycle Protection: 3 minutes delay start, available in cool-mode only Dimension: 125W x 90Hx 35D mm Switching Differential: A/AF Mode: 0.4/0.8/1.2/1.6/2°F, 0.2/0.4/0.6/0.8/1°C Default: 0.8°F/0.4°C. F Mode: 1.2/2/4/6°F, 0.6/1/2/3°C Default: 2°F/1°C Material: Non flammable plastic