I think I have water hammer

youcancallmeal

Moved into a newly built house about a year ago which has an air to water heat pump with alu rads. Shortly after flushing the downstairs toilet there is a short series of loud knocking/creaking noises that lasts a couple of seconds and can be heard throughout the house. Sometimes it will then continue making the knocking noise roughly every 5 mins for hours, flushing toilet again will stop it.

Best I can tell the noise is coming from behind the walls somewhere between the toilet and the attic. I did a bit of googling and it sounds very much like what is described here https://www.ragsdaleair.com/blog/what-is-the-loud-banging-noise-after-i-flush-the-toilet-4/
It has been getting louder and more regular recently so I really need to get something done. I think it's too late now to have the builder look at it as they wouldn't return my calls on another issue I had with a shower leak a few weeks ago. I'm wondering am I going to have to get a plumber out to look at this or can I try resolve it myself by draining the system? Also does the air to water heating system play any part in water hammer or is it separate system completely?

agusta

youcancallmeal wrote: »

Moved into a newly built house about a year ago which has an air to water heat pump with alu rads. Shortly after flushing the downstairs toilet there is a short series of loud knocking/creaking noises that lasts a couple of seconds and can be heard throughout the house. Sometimes it will then continue making the knocking noise roughly every 5 mins for hours, flushing toilet again will stop it.

Best I can tell the noise is coming from behind the walls somewhere between the toilet and the attic. I did a bit of googling and it sounds very much like what is described here https://www.ragsdaleair.com/blog/what-is-the-loud-banging-noise-after-i-flush-the-toilet-4/
It has been getting louder and more regular recently so I really need to get something done. I think it's too late now to have the builder look at it as they wouldn't return my calls on another issue I had with a shower leak a few weeks ago. I'm wondering am I going to have to get a plumber out to look at this or can I try resolve it myself by draining the system? Also does the air to water heating system play any part in water hammer or is it separate system completely?

The air to water is separate. is the water feeding the toilet coming from a tank in the attic or fed off the mains water

youcancallmeal

agusta wrote: »

The air to water is separate. is the water feeding the toilet coming from a tank in the attic or fed off the mains water

I'm not sure exactly, how do I know?
I took the lid off the cistern on the downstairs toilet to observe what's happening when the hammering occurs. See attached video, I'm guessing the bubbles coming out of that black rubber thing there is the problem right?

Edit: Having trouble making the video small enough to attach, I'll try YouTube

Ajsoprano

You could try an equilibrium stopcock in the attic tank and clip all the mains pipes you can find but it could be an unclipped vibrating pipe behind the wall. It’s hard to tell on the Internet.

youcancallmeal

Okay here's the video https://youtu.be/o8duSXlAT60

I was on to the plumber who worked on the house when it was being built and I think he's going to be able to come out to me next week. It looks like it might be an easy enough fix