T6865 digital thermostats are designed for application of 3-speed fan and modulating valves in fan coil system. Including: 2-pipe cool only/heat only/manual changeover Ventilation mode  Manual or automatic 3-speed fan control modulating valve control Fan speed can be selected to automatic or manual 3-speed control mode In ventilation mode, fan only support manual speed control Features: Super modern appearance design, suitable for office, hotel and residential building Slim design, direct installation on 86×86mm box or 3×3inch box Stylish and elegant green/blue backlight with white colour ring 2-pipe integrated into one unit with easy configuration Big LCD display with English and icons Easy to install and set-up, Time on/off function Selectable room temperature or setpoint temperature display Manual or automatic fan speed selection Energy saving mode activation by button press or dry contact (key card) Adjustment of display room temperature Temperature unit either ℃ or ℉ User setting can be kept when power off Freezing protection function available Lock or unlock keys or part of keys in Installer Set-up ( ISU ) Heat and cool setpoint limitation for energy saving 24VAC power supply, 230VAC fan load, 4A resistive and 2A inductive switch rating