Johnson Controls P32AC-2C Sensitive Differential Pressure Switch w/ “U” Bracket (0.05″ to 5.0″ WC)

The P32 differential pressure switch is used to sense flow of air in ducts. When used with electric strip heaters, the switch can be wired to open the circuit and deenergize the heaters when air flow stops.

This switch senses a change in the differential pressure (either velocity pressure or pressure drop across a fixed restriction in the duct) as air flow in the duct changes. The differential pressure, as sensed by the two sensing ports, is applied to the two sides of a diaphragm in the control. The spring-loaded diaphragm moves and actuates the switch.  The P32 can also be used to detect small positive gage pressure by using only the high-pressure connection and leaving the low-pressure connector open, or to detect a vacuum by using only the low-pressure connection and leaving the high-pressure connector open to ambient pressure. Switches are factory set at the bottom of the operating range with
the diaphragm in a vertical plane.

Features and Benefits

• Air proving with electric duct heaters.
• Maximum air flow controller for variable air volume systems.
• Reheat duct powered systems.
• Detection of icing of air conditioning coils and initiation of defrost cycle.
• Clogged filter detection
• Easy-to-read set point scale.
• Small and compact.
• Versatile mounting options.