Flow Capacity of 28-BFV Brass Float Valves

The flow capacity of 28-BFV brass float valves at various inlet pressures is indicated in the flow capacity chart below.

Unfortunately, flow velocity is often overlooked. Excessive flow velocity can result in number of issues, including water turbulence in the tank which can result in the float ball bouncing around and being unable to seal off the valve properly. See the velocity guide chart below. You will notice that the GPM rating at the suggested 5 fps velocity limits the capacity of the valves from what they could potentially deliver at higher inlet pressures indicated in the flow capacity chart.

When the float valves are used at higher flow velocities problems start to occur. In some cases, sealing can be achieved by using a longer float rod, to increase leverage, with a larger diameter float ball, with greater buoyancy, to overcome turbulence issues. Turbulence issues are caused by water being discharged into the tank at a high speed rate and force.

Additional Resources / Articles of Interest.

https://support.boshart.com/float-valve-selection-and-installation-for-trouble-free-operation

https://support.boshart.com/what-length-of-float-rod-do-i-need

https://support.boshart.com/what-size-of-float-ball-do-i-need

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