The Johnson Controls P40AA-1C Pneumatic SENSITIVE DIFF; Differential Air Pressure Switch; Air FLOW; .12/2.0 WC CLOSE HIGH PNEUMATIC
The P40 pressure switch is used to sense the flow of air in ducts. The switch is a sensitive pneumatic device which can be used as a fan status sensor or a differential pressure switch. The switch has an adjustable switching set point from .12 to 2.0 in. W.C. (.03 to .50 kPa).
All Series P40 switches are designed for use only as operating controls. Where an operating control failure would result in personal injury and/or loss of property, it is the responsibility of the installer to add devices (safety, limit controls) or systems (alarm, supervisory systems) that protect against, or warn of, control failure.