View Full Version : Question about flow through a ball valve...

10-17-2009, 06:29 PM
I also posted this in the irrigation forums, but I wanted to hear it from you as well.

I sell pvc ball valves, check valves, unions and a bunch of other items.

I just had a buyer complain that my 4" PVC Ball Valves are not full port as advertised. I pulled out my calipers and sure it enough, it measured 3 3/4" in the throat, not 4".

Is there that much flow loss in that 1/4"? I have never noticed it in either irrigation nor pond installs. Has anyone ever seen a 4" PVC Ball Valve that was truly 4" inside?



STL Ponds and Waterfalls
10-17-2009, 06:33 PM
I never thought twice about them. I usually just installed them and went on with the rest of the job. I guess I need to do some checking on the valves I use.:confused:

XStream Aquatics
10-24-2009, 04:10 PM
There is alot of loss in the 1/4"!!!!!!!!!!!!!!!!!!!!!!!!!

XStream Aquatics
10-24-2009, 04:16 PM
I will post a chart of friction loss and head on fittings when I get back in town.