Variable Frequency Drive (VFD) systems operate by continuously adjusting pump speed to match system demand. This causes frequent changes in flow velocity and pressure that can negatively affect standard poppet-style check valves.
Poppet-style check valves rely on a spring-loaded disc that opens and closes in response to flow. In VFD applications, the varying flow conditions can cause the poppet to cycle rapidly, chatter, or partially open and close repeatedly. This can lead to premature wear of internal components, increased noise and vibration, reduced valve life, and potential water hammer issues.
For VFD-controlled pumping systems, check valves specifically designed for variable flow conditions should be used. Boshart carries 2 series of VFD check valves to support these systems. Both are made from ductile iron.
Flomatic also carries bronze and brass VFD check valves:
https://www.flomatic.com/valves/vfd/80evfd-100evfd/
https://www.flomatic.com/valves/vfd/100mevfd/
https://www.flomatic.com/valves/vfd/80ae-80aevfd/
https://www.flomatic.com/valves/vfd/80bevfd/
https://www.flomatic.com/valves/vfd/80ce-80cevfd/
https://www.flomatic.com/valves/vfd/80xbevfd/
NOTE: Always consult the valve manufacturer's recommendations when selecting a check valve for use in a VFD system.