A4100 Trouchscreen Programmable is a friendly interface, 7-day programmable thermostat that provides universal heating, cooling, air conditioning or heat pump system compatibility. Through software or hardware parameter setting, this thermostat adapts quickly to suit the variations required in different control projects. MODBUS protocal is available. The installer is able to configure A4100 to control Heat Pump system (with auxiliary or emergency heating if necessary), gas/ oil / electric boiler heating system with add on cooling, control high and low balance points as well as the number of heating and cooling stages needing precise control.Features: Large, clear display with backlight shows the current and set temperature and thermostat in the dark. Menu-driven programming makes setup effortless. Touchscreen interactions, Surface mount Real-time clock keeps time during power failures Change/check reminders let you know when to do maintenance or replace filters Various Hold options allow you to override the program schedule, as desired. A4100 Touchscreen programmable thermostat enjoy a great wide range of application fields. Additional features Auto changeover Selectable programmable or manual mode Heat cool or heat pump (O/B) logic Add on & Emergency Heat Control High & Low balance points Single or 3 speed fan control Keyboard and/or Temperature Locks Programmable occupancy inputs Adaptive Recovery PIN protected menus (installer PIN) Outside air temperature display 24VAC powered with memory backup Remote temperature sensors available RS485 interface MODBUS protocol available