Description
The Johnson Controls P74FA-1 SPDT Differential Switch is a stable and flexible device that is applied to measure the pressure differential in air supply and return lines in HVAC systems. Constructed of brass for long service, it is easy to operate with a turn-screw system that allows the user to set the pressure between 8 PSI and 60 PSI. The switch employs a pressure-sensing component that responds to fluctuations in differential pressure. When the pressure difference gets to the set point, the switch gives either an on or off signal. This signal can then be used to regulate diverse HVAC equipment to achieve the best performance and efficiency of the system.
