Replacing CH pipes due to noise on start up

Morning all

After some advicee please guys.

When my CH starts up (and also the HW) the pipes make the most horrendous noise on start up. The only way I can describe it is it's sound like a snapping / hammering noise and it is loud.

This noise is always on start up in the morning and constantly wakes me up. It has been like this since we moved in several years ago and I have finally had enough.

The person who installed the CH made a right hash of the pipe work and joists that are under the floor boards. last year I wrapped the pipework in a thin layer of foam and this did help but its gone back to making the loud noise now. I assume the pipework is too tight in the joist cutouts and this is causing the pipework to bang together on start up.

The pipe work is not clipped in any areas under the floorboards and just seems to be wedged. The pipework is 22mm and 4 runs of pipe run alongside together.

So the options I am thinking of is to:

Replace the 22mm pipework under floorboards with 15mm but not sure if this will add increased pressure to the boiler and pump or is this not a good idea? The reson for the 15mm is so I can get it clipped and leave space between each pipe.

Replace the 22mm Copper pipe with Speedfit pipe and hope that this will stop the "snapping noise"

If it helps the Boiler is an old Apollo Thorn.

Any help advise is much apprciated.

Thank you

I feel your pain, as I also have problem pipework similar to yours. Is yours a recent (ish) build by any chance? I've just gone down the clip and add foam route that you have already tried. This has helped a little but I know it's only a temporary bodge.

You could notch the joists lower (if safe to do so) and re-lay the pipework so it's not so tight on the floorboards. Mine just aren't notched low enough in the first place so the pipes are tight on the floorboards. I'm not even sure clipping them down is the best way to go either as they're always going to expand and move a little. To me it seems you have to brace the pipework but still allow a little bit of wriggle room to allow for heating up/cooling down.

Plastic piping, so I'm told, is much less noisy than copper in this respect so that's another idea. I would expect you'll need to keep 22mm for the flow and return rather than replace with 15mm but I'm no plumber so I'm sure someone else can advise.

Alternatively can you pinpoint the exact point where it is knocking? Although the noise is transmitted throughout the pipework (upstairs I'm guessing?), it's probably coming from one or two areas that you could focus on.

Thanks for your reply.

I can sort of pinpoint the various areas of the noise but once I remove the floorboards to physically investigate the sound sort of halfs and because there is so much "snapping" on different parts I cannot keep up with it!

Have you tried running the heating with the floorboards removed? It may not be practical for you but if you can it might help to trace/eliminate the problem areas.

I would avoid reducing the pipe size if possible as it could lead to performance problems, depending on how your system is piped.

As you say, the pipes are likely held too tightly between the floorboards above and the joists below so when they expand there are discrete movements producing the knocking noises.

It may only require removal of a small thickness of wood to slacken off this grip on the pipes and dramatically reduce the noise.

I do believe that because they are held so tightly in place that is a major factor in the knocking. As cutting the joists wont cost me a penny I will go down that avenue first,

If you employ the cheapest possible installer then don't expect a proper job!

The joist notch should be large enough to fit the pipe loosely and the pipe wrapped in felt in the notch.

I quote to do these jobs properly but customers like you go for the cheaper quotes from bodgers like your installer!

Your boiler is outdated and not very efficient. I suppose you are not replacing it because you want to save money at the expense of higher fuel bills and more contribution to the global warming.

Tony

Agile said:

If you employ the cheapest possible installer then don't expect a proper job!

The joist notch should be large enough to fit the pipe loosely and the pipe wrapped in felt in the notch.

I quote to do these jobs properly but customers like you go for the cheaper quotes from bodgers like your installer!

Your boiler is outdated and not very efficient. I suppose you are not replacing it because you want to save money at the expense of higher fuel bills and more contribution to the global warming.

Tony

Click to expand...

I can only assume Tony you didn't read the my post properly as your response is a pathetic.

The system came with the house - I didnt get it installed.
I will notch the joists myself as it wont cost anything - thanks for the tip about the felt.
Im not replacing the boiler because its not broken.

Well it`s not one of my installs in Sussex You could try a silicone spray on the timber under the pipes

Nice one Tony
How rude was that?

The tone of most of his replies follow the same pattern.