View Full Version : Hammering / Vibration pipes

Ken Birrenbach
02-22-2007, 09:27 AM
I returned from a months absence in early February, I live in Wisconsin, and discovered that the pipes in my rambler style house would rap/hammer violently whenever the water was turned on whether it was a water faucet, shower, toilet flush, etc. The noise stopped when the water was shut off. I replaced a Watts pressure regulator model N35B U with a Watts model N55 BU M1. The hammering stopped, but now I have a medium pitched hum whenever the water is turned on anywhere in the house. I tried raising the pressure setting and reducing it, also. Neither adjustment seems to have a noticeable affend on the hum. I have tried to reach the Watts help line but cannot access the web site. Can you give me any ideas what to try next? Thanks for your help. Ken

US Parts Center
02-22-2007, 10:31 AM
Are you in an area with new home growth?

Ken Birrenbach
02-23-2007, 07:55 AM
We live in an established neighborhood. There have been no new homes built in this neighborhood for 4 years. We do have about 100 psi water pressure on the main line. Ken

02-23-2007, 09:17 AM
Do you notice this more after having run hot water, or does it matter?

Do you have an expansion tank in the system? The reason I ask is thatwith a PRV, you need one. After running hot water, the cold, dense stuff that replaces it expands when it is heated, increasing the pressure of the systems in the house until you again run some water. This pressure can peak quite high, enough sometimes to pop the T&P valve on the water heater. If the PRV isn't working perfectly, and you don't have an expansion tank, or it is shot, that excessive pressure can flow backwards out of the PRV and make noise. It could have been that the older one you replaced was just leaking worse and banging on/off during this - the new one is fighting harder, and only humming.

Does the noise eventually stop? Maybe when the WH turns off and the water isn't expanding any more?

Pick up a pressure gauge and see what pressure you actually have while this is happening. It wouldn't hurt to have two, one before and one after the prv.

Ken Birrenbach
02-24-2007, 09:39 AM
It doesn't matter if we turn on a hot or a cold tap. We get the hum whenever the water is flowing, flush the toilet or whatever. But, no we don't have an expansion tank. In fact, reading questions and answers in Terry Love's plumbing and heating advise forum, is the first I heard about needing one. We have been home owners for over fifty years and have not had such a problem before. I will, however get a pressure gage and find out what the water pressure is and if it fluctuates.

Ken Birrenbach
03-01-2007, 07:04 AM
I hooked up a pressure gage on the faucet in the laundry tub. I have 63-64 psi. when I turned on the tap in the hand washing sink next to the laundry tub, the pressure dropped to 60-61 psi. Is that a normal drop? Is it meaningful? What next? Should I replace the washers on either side of the pressure regulator? Ken

03-01-2007, 07:28 AM
what next? Hmm, a week ago you said
... I have tried to reach the Watts help line... What did the guys from 1-800-tech support tell you?

What noises occur when you open a faucet just enough to get the smallest trickle?

Have you got access to the pipes in several locations?


Ken Birrenbach
03-05-2007, 12:01 PM
The sound is there with the slightest trickle. By that I mean when there is a stream less than 1/8 inch across. I am not sure what you mean by access to pipes in several places. The water inlet is in the basement floor. I have a ball valve shutoff between there and the pressure regulator. The pipes are all exposed in the basement ceiling until they go up to the kitchen, bathroom or go out the wall to feed the hose bibbs. Ken

03-05-2007, 04:16 PM
I've had many problems like this and sometimes it's hard to find. Many times a bad toilet ballcock is to blame. When you run water the pressure drops slightly causing the ballcock to fill slowly and sometimes it will vibrate the entire house. Shut one toilet off at a time to check it. I find AS toilets the culprit. TB

03-05-2007, 04:31 PM
WHen you have a PRV, it is normally required to have an expansion tank. If you have not been popping the T&P valve on the water heater, there is probably a valve that is leaking. THe one most likely to do that without you noticing is a toilet, since it can go down the drain if it overflows without you noticing much.