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, the 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.