Issue with hot water from Worcester CDI 24 combi boiler

[stockdale]

Hello,


Hope someone can help.


I have been doing some reading about similar issues to mine but cannot find any real answer on different forums.


I recently moved in to a new property that has a Worcester 24 CDI combi boiler. Every once in a while, when there is prolonged hot water use (after washing the dishes or having a shower for example), as soon as the hot water is turned off, a banging noise can be heard coming from the boiler.


The boiler was serviced a couple of months ago and the engineer topped up the water in the boiler after I reported this behaviour. The problem stopped but just came back a few days ago.


Has anyone experienced this problem before and what should be the pressure of the system when cold?


I read that between 1 and 1.5 bar should be fine.


Many thanks.

 

[WHPES]

The system pressure should be 1 bar typically when cold but this is nothing to do with your problem.

Problem is probably either water hammer on shut off (does it still do it if you close the tap slowly?) or a diverter valve to the heat exchanger suddenly slamming shut

 

[stockdale]

Good point about closing the tap slowly. I never tried so will try that and see if it still makes the hammering noise, although I have not heard this noise for a couple of days now.

If the problem comes from either area you have mentioned, any idea on how to fix this or how much it would cost for an engineer to come and fix this for me?

Many thanks for your help by the way, much appreciated.