The selection option for Optional Equipment is Calibration Solenoid Valve (BO). This BO is an output to interface to one or more Calibration Solenoid Valves, and is created if the Calibration Solenoid Valve BO selection is checked. This selection is always available. Select this option to use calibration solenoid valves during the autocalibration process for spaces that must remain in control at all times (for example, labs with supply exhaust boxes or hospital rooms). All damper outputs stay at their current value during this 10 second process. The BO is connected to the State Selector through the Calibration Solenoid Pass Through module. The BO zeroes the differential pressure for the Differential Pressure sensor during autocalibration. The effective stroke time for the autocalibration sequence module changes to 10 seconds when this option is selected to speed up the process. Use this BO for all Differential Pressure sensors in the system (Hot Deck, Cold Deck, Total Flow, and Exhaust Box).