Products

P74JA Type Differential Pressure Control with Floating Action Switch
The P74JA differential pressure control is commonly used on water systems to control a pressure differential between supply and return lines. The control’s SPDT floating action contacts position a motor actuated valve operated by a Johnson Controls M81 or Series M100A motor actuator. In atypical application the valve is located in a bypass line around the system pump. When the system pressure differential increase above the control’s set point, the valve opens further. More water is diverted through the bypass valve resulting in a reduction in system pressure differential. A reduction in the pressure differential causes the valve to begin closing and reuslts in an increase in system pressure differential.
The P74JA is suitable for use on other air or liquid pressure differential applications where SPDT non-snap acting switching is desired.
All Series P74 differential pressure controls 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. Read more in PDF