Tapping noise in CH pipes

Immediatly after the boiler switches on the sharp tapping sound starts. It seems to be located in the pipe which runs from the boiler to the radiators an d is very irrating and very loud.Can anyone help me solve this problem?

Could be expansion noises in the pipe as it heats up, are the pipes secured correctly? i.e. clipped and not swaying in the breeze.

Hello,
I had the same problem with my heating system. It starts making a rattling noise as soon as the Central Heating function comes on. It was driving me nuts, so I swapped the pump for a new one. That made no difference. Then I partially closed the throttle valve beneath the pump. This stopped the noise but the heating didn't work so well either. I then tried turning off the radiators while the system was running. By a process of trial and error I found that the heating would run completely silently and efficiently if two particular radiators upstairs were turned off (all other radiators opened again). Note that the two radiators that were turned off did NOT have thermostatic valves but rather ropey looking manual valves. Other radiators upstairs (and downstairs) working correctly. I have been trying to cure this problem for 2 years now (since we moved into the house), and as a celibration we left the new "quiet" heating on all night!!! I can only assume that the manual valves on the radiators that I have turned off have fallen to bits inside the mechanism, and that a certain flow rate cause these loose parts to rattle about. I am going to get a pipe freezing kit, so that I can replace the old valves without draining the system.
Does this help you?

Rich

Hi Morfina

Did you solve your tapping pipes problem? I have the exact same problem as you. Just two problem radiators (in the same room) driving me nuts. Did you find a resolution? Thanks for your help!

Steve

Hi there. Sorry to ressurect an old thread, but on searching Google this post was exactly what I was looking for.

I moved house about seven months ago and have had no problems with our gas boiler until the last few days. It keeps overheating and automatically shutting down, which means I have to manually reset it again. I've tried turning the valve down that's under the panel on the front, but it makes no difference. Now, whenever the boiler comes on (like this morning at 5 o'clock), there is a loud tapping/thumping noise coming from underneath our bedroom floorboards (where the pipes run). CH is not on, and hasn't been for months, this is just occurring for water heating.

Any help would be appreciated because I'm dreading a hefty bill.