Duct Static Pressure: Dehumidification Mode

Dehumidification mode activates when the space humidity rises above the dehumidification setpoint. The cooling coil cools the air in order to reduce the humidity level before the Dehumidification coil heats the air back up to the set temp. The fan modulates to help efficiently move the air. The cooling coil controls to a leaving coil temperature while the reheat coil controls to a discharge air temperature.

As VAV boxes close, the pressure in the system rises. This causes the fan to reduce speed in order to maintain a constant supply duct pressure.