Plumbing Humming is back!

[moorem]

Hi. I am at my wits end here. This is my third post to solve this annoying problem. Here's what's going on. There was a huge humming sound in my basement. I have added "quiet pipes" brand hammer stoppers on both my hot and cold water lines. Then I installed a new Pressure Reducing Valve. Then I pulled off the gate valve on my water heater (the cold shutoff) and installed a brand new one. The pipes do not always hum now, but it seems random and happens at least once or twice a day. It doesn't happen when using any specific device in the house, but almost any of them can seem to activate the noise. When I hear the humming I can actually modulate the sound by runnning down into the basement and opening and closing the new gate valve on the water heater. So, I know for a fact that it is in my cold water line and seems to have something to do with the heater. I can put my hand anywhere along the cold line in the basement and feel the humming. What else can this problem possibly be from? It seems like I've replaced almost everything that could be responsible. Thanks for all the help.

[HayZee518]

The pressure regulator has a spring and a rubber seat inside it. It acts just like a pressure regulator on an oxy-acetylene gas setup. In the oxy-gas setup it's reducing the 2000# gas setup to a usuable 0-40 psi. It dies this by means of a spring and diaphragm.
Your water regulator is built the same way - a spring loaded diaphragm acting against the city water pressure inlet and regulating the output so you don't blow up things.

[HayZee518]

How do I size a regulator?

Sizing of a regulator is best determined using known system demands. The smaller the demand, the smaller the regulator required to satisfy that demand. Once the demand is established refer to the published flow curves for the most appropriate size. A good rule of thumb is to size a regulator so that the fall-off will be between 10 and 15 psi.