Honeywell T6861H2WB Large LCD digital thermostats are designed for the application of a 3-speed fan and valves in a fan coil system. The fan can be selected as a manual or automatic 3-speed operation. In Manual mode, the fan is switched to the selected speed via control output Gh, Gm, Gl. While in automatic mode, fan speed depends on the difference between room temperature and setpoint. When the room temperature reaches setpoint, the valve will be closed and meanwhile, the fan will be closed either.