Home>Discussions>PLUMBING>Update on Random Noise in Pipes - Expansion Tank!!!
2 posts / 0 new
Last post
Update on Random Noise in Pipes - Expansion Tank!!!

Hi All, well, I have an update for you about the noise we have been experience in our pipes. We had a new plumber come to our house on Monday and reduce the pressure PSI is now set to 52. However, that night we still heard the noise. We called the plumber the next day and he said his next step would be to replace the PRV, yet again, because he was not sure that the PRV we have allows for Thermal By-pass. Well, instead of just agreeing to yet another prices thing. I called the company that makes this PRV (Wilson-Zurn). I spoke to a very nice product service manager and explained all of my troubles. He said, he truly believes that what we are experiencing is Thermal Expansion. He said that, because of the colder temp (we live outside Washington, DC.) that the problem came back because of the amount of pressure it takes to heat the cold water coming in to our house. Also, he mentioned that Thermal expansion causes leaky toilets, which we have had three (out of 4). We had fixed all these toilets, basically closing up our system more. He said his product does allow for Thermal bypass but only up to the amount that the street is set at. So from what I understand, our house is set to 52 psi and the street is 100. So only 48 psi could go back. So, the long of the short of it is that we had the plumber come back on Wed. and put an expansion tank on our water heater. Wednesday night WE DID NOT HEAR THE NOISE FOR THE FIRST TIME SINCE THE WEEK BEFORE CHRISTMAS.... So we thought our problem was solved. However, we did hear a little rumbling this morning and a little rumbling tonight before I wrote this thread.

I did call the very nice customer service man back and he said that if the plumber did not set the pressure at the same as the house - that could be causing a little problem. I was not happy with the plumber that came because he really wanted to replace the PRV and did not think we had an expansion problem. Because he said that if our water was turned off we should not have any noises. And remember I made the comment that we had turned our water off and yet we still heard the noise that night. (not as loud but we heard it). Well, the customer product man said we still heard the noise because our pipes were hot from the heat in our house and because the wh was still set for vacation. He told me to run a small amount of cold water that night and if the noise went away or got less then we would know it is expansion. Well, that night we did it and the noise was less, much less.

So, where we stand. We got the expansion tank - the noise went away for the day - but now even as I write this we can still hear a little rumbling every once in a while. So should we call the plumber back to check the pressure in the tank is set to the pressure in the house? Or should we call a new plumber?(one that is a little nicer to their customers) or just ignore it?

Re: Update on Random Noise in Pipes - Expansion Tank!!!


You still have the noise intermittently in spite of all the expense you've been put thru. Sorry.

Your plumber reminds me of the auto mechanic who doesn't have the ability or instruments to diagnose your problem, so he starts slapping in expensive replacement parts based on his best guess.

My best guess is something you can test yourself without any cost, and even if it turns out not to be the problem, you will have conclusively eliminated one possible source:

I suspect that the WH is rumbling due to a build-up of hard water scale. IT IS A MISTAKE to think you have tested for this by adjusting the setting of the the thermostat to "vacation", because this merely lowers the temperature at which the burner will fire--it will still fire when the water temperature drops low enough. You must turn off the WH gas supply valve completely to make this test. If the noise goes away, it means you will either have to replace the WH or live with the noise. Or you could try de-scaling the WH with "lime-eater" or "mag-erad".

This rumbling, hammering sound is actually due to small explosions of steam from pockets of water trapped in the scale build-up. Check my post to rhuffman on Jan. 16 for the full explanation.

This will happen whether or not there is an expansion tank installed, and whether or not the PRV has a bypass.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.