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James I
James I,
Category: Plumbing
Satisfied Customers: 2159
Experience:  Expert at Just Answer
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When our central heating goes on we do get some clanking

Customer Question

When our central heating goes on we do get some clanking from the (water filled ) radiators as it heats up and everything expands. I would like to stop the knocking noises and have looked for places where pipes might rub against joists or floor boards. Is it possible that the sounds come from behind the radiators, i.e. from the fittings that allow expansion while holding them up against the wall? Any thoughts much appreciated.
Submitted: 7 months ago.
Category: Plumbing
Expert:  James I replied 7 months ago.

What you are describing is water hammer, you need a water hammer arrestor such as the one here which takes the shock of water flowing and suddenly stopping and prevents pipes shaking. The cause of water hammer could be TRV on radiators opening or closing, pumps starting and stopping or even a boiler starting up.

In terms of location of the noise the pipes cleats holding on the wall could be a cause, but this doesnt sound like an expansion issue,