The TF428 series digital thermostat is designed for 3-speed fan and valve control in a fan coil system, including: 2-pipe cool only/heat only/manual changeover 4-pipe cool/heat manual /automatic changeover Ventilation mode Manual or automatic 3-speed fan control Water valve control Besides the basic controls, TF428 series featuring CPH (Cycle Per Hour) better maintains the room temperature to the setpoint and Random Start-up Function would help to maintain power grid stability. In addition, Honeywell Memorized Time Off Function can automatically turn off the thermostat to save energy.  Features: Memorized time off Cycle Per Hour (CPH) Random startup Remote temperature sensor optional Energy saving mode optional LCD display with simple user interface Room temperature or setpoint temperature display selectable Manual or automatic fan speed selectable Temperature units in either °C or °F User setting can be stored with power loss Freeze protection available Four keypad lock options Heating and cooling setpoint limitation