Last Friday, I worked at a house with low water pressure (40-45 psi, municipal water, not a private well). In preparation to install a booster pump in the near future, I piped a bypass into the 3/4" copper vertical riser off the water meter. Besides the water meter, there is an existing dual check backflow preventer and an expansion tank. About three feet above the meter, I cut in a 3/4" copper tee, with a short piece of copper and a ball valve on the tee's horizontal branch. I cut another tee and ball valve into the vertical riser, about 10 inches above the first tee. In between the two tees, I put a third ball valve on the riser. Also on the riser, I installed a tee with a pressure gage, downstream of the bypass setup. The purpose of doing this is so we won't need to shut the water down when we return to install the booster pump.

Anyway, after installing all this, I noticed a very loud whining/moaning noise whenever water was being used, especially by an outside hose faucet, but I also heard it when the kitchen faucet was running. I thought it might have been a screw-on, hose-thread vacuum breaker, since I've heard those make a similar noise, but there was none. Then I thought it might the pressure gage vibrating, but I replaced the gage with a plug, to no avail. I put my ear to the water meter and to a whole-house water filter downstream, thinking either one of those might be the noise source, but it's hard to tell if either one is the noise source. The homeowner said the filter has not been changed in at least two years, so could there be some restriction causing the noise?

Then, I had one final thought: Could the two tees I cut into the vertical water main riser be causing some kind of turbulence, thus making noise (like a veturi effect)? Should the tees have been spaced farther than 10 inches apart? I've used this same type of bypass setup for pressure reducing valves or water filters in the past, and never had an issue with noise. Also, this is the first time I've ever worked in this (old) house, so I don't know if the noise existing prior to me working there (I didn't think to ask that question, but I assume it didn't exist before, since the homeowners probably would have complained about a noise this loud and annoying). I'm stumped!!

40-45 psi is NOT repeat NOT low water pressure

it may be insufficient to supply desired volume because of too small piping but, to repeat,

is NOT low municipal water pressure

does the noise persist when operating on the newly installed bypass? (new loop valved off)

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Yes, it is in bypass mode already. The pump is not installed yet, so I cannot see if the noise exists otherwise. (The ball valves going to and from the future pump are closed, and the third ball valve, which is on the vertical riser and between the two tees, is open so the homeowners can continue to have water in the meantime.)

are the valves 'full port' type ?

if not, why not ?!

Bore Size

The difference between a standard ball valve and a full-port ball valve is in the size of the ball and bore in relation to the nominal pipe size of the valve. For example, the bore size in a 3/4-inch full-port ball valve is 3/4-inch in diameter, while the bore diameter in a standard ball valve is 1/2-inch in diameter. Ball sizes are in proportion to bore sizes. The 1/2-inch diameter is the nominal size of the next smaller pipe. This is typical. Full-port bore size equals pipe size; standard-port bore size is the next smaller pipe size.


Flow Coefficient

The flow coefficient is a measure of the resistance to flow of a given part of a fluid system. It is used to calculate the length of straight pipe equivalent to an elbow or valve or anything else that affects the flow. The flow coefficient for a full-port ball valve is almost as low as that of straight pipe so it provides minimal resistance to flow and thus creates only a small pressure drop. The standard-port ball valve has a higher flow coefficient and thus causes a larger pressure drop for a given flow.



Read more : [www.ehow.com]

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Yes, they are full port ball valves (the only kind I buy).

? gremlins ?

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638