Originally posted by David Logue:
Thanks for your help. I do not have the FPS or the pipe size (1 inch I think though). However, I believe you are correct in your diagnosis. I went downstairs and turned the main valve to our house down (almost to closed) and the squeals have subsided. I also had to turn the flow into one toilet down. The water pressure to the faucets and tubs seem to be about the same so it evidently did not slow the water down too much by turning the flow into the house down.
I have to ask you . . . is there a way to correct the problem without turning down the flow to the house from the main line? A new valve or something that lowers flow?
I really appreciate your help.
No problem David, OK lets assume it is too much velocity then you can do the following.
Under most sinks there is either an angle valve or a straight valve which if properly specified was a globe type which is designed for throttling unlike a gate valve (normally found on the main)
All you have to do is close each of these valves slightly until the noise stops.
As for one inch pipe lets say you have 60 PSI in coming pressure your velocity would be around 27 FPS If everything is flowing full blast and we are not taking friction losses into consideration.
Your “Flow rate” is about 67.5 GPM
So we can figure the installing contractor may have slightly miscalculated the incoming pressure and here is where the globe valves do their job of fine tuning the system so as not to cause excessive noise or erosion of the piping system.
One more point turning down a valve does NOT decrease the pressure per say as pressure remains constant BUT you do decrease the volume as your making the passage way smaller more resistence like a voltage drop in electricity when you have brown outs.
You are causing pressure drop ONLY because you are adding more restriction BUT if you put a gauge on this partically closed valve with a no running condition you would see the pressure remains the same.
Have a GREAT WEEK END