Home>Discussions>PLUMBING>Hearing knocking noise from hot water pipe
4 posts / 0 new
Last post
Josiet
Hearing knocking noise from hot water pipe
Josiet

I had a new mod con Triangle Tube boiler installed before I moved to my house. I started to notice that when someone turns the hot water on, the pipe makes a knocking sound. Is this normal?

A. Spruce
Re: Hearing knocking noise from hot water pipe
A. Spruce

"Normal" would depend on the age of the house and plumbing. Because you say it is the hot water making the knocking noise, I would suspect that it is expansion/contraction of the hot line where it crosses through framing members. As the pipe moves, it squeaks as it rubs against whatever is touching it. How can a pipe "knock" when it's rubbing against something, well, it's not unlike rubbing your fingers across a balloon, it's the same sound and same principle.

dj1
Re: Hearing knocking noise from hot water pipe
dj1

A physical inspection is needed. There are just too many possibilities.

Some of them:
- As mentioned, pipe expansion.
- Type of pipes and pipe clamps
- Water hammer.
- Location of the noise.
- and more...

I can only suggest to get a plumber(s) to check it.

brewster
Re: Hearing knocking noise from hot water pipe
brewster
Josiet wrote:

I had a new mod con Triangle Tube boiler installed before I moved to my house. I started to notice that when someone turns the hot water on, the pipe makes a knocking sound. Is this normal?

Josiet,

No, it is not normal, and from the sound/descriptions of your post the installer is completely responsible for coming back to your house free of charge & correcting the problem because he/she messed up somewhere in the installation process & perhaps air is being sucked into the HW line every time a faucet is turned on, due to improperly installed piping/ loose fitting, etc. Call the installer right away.

Sponsored Stories

TV Listings

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