Boiler bangs when hot water used

How to remove the air from your boiler heater The boiler is probably air bound, and the system needs to be purged of air. The link is for an informative video. It will explain the various parts/ produdures to purge the system.
Bleeding Hot Water Boiler

The noise you refer to is called Kettling, it is caused by the hot water in your boiler not being able to leave the boiler quick enough, if the problem developed quickly and your system is a "fully pumped " system this would generally point to your pump either has failed or is on its way out, i.e . your radiators would not heat up as the hot water is stuck in the boiler hence the banging......( if you know where the pump is you can generally feel if it is running by a small vibration ) if you have gravity hot water and pumped heating circuit then I would assume that it is noisy when just doing HW, and the banging is a problem that has gradually got worse it can indicate that the boiler is scaling up (are you in a hard water area). if this is correct there are various additives that can be put in the system to help quieten it down, I suggest you really need a heating engineer to diagnose fully.

There should be a pressure drain to purge out all the air. Sound like there is an air bubble in the system somewhere.

you have sludge in your in your rads need a rad flush to clear it out .

first check for loose pipes the you might want to add a damper on the pipe to absorb the hammering just t in a piece of pipe and make it go higher than the pipe with the noise and put a cap on topp of that

Hello,You need to install a domestic/high pressure extrol/expansion tank on your cold water pipe.Should slove noise.

hi you could be drawing air into the system try bleeding the system check all seals and if ok tighten all connections

it sounds like water hammer, you need to install a water hammer device at the water outlet of the boiler. aviliable from any plumbing stores.

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