Hi,
> I have a combination boiler (Vokera). Yesterday I drained the system,
> following the instructions in th manual, to do some decorating. After
> installing back the radiator I had removed earlier, I filled up the system
> (again, following the instructions in the manual).
>
> Since then, when we turn on the hot water tap (bath, shower, kitchen,
> etc...) the hot water goes on and off all the time. At first you get hot
> water as normal for about 15 - 20 seconds, then the boiler will stop (you
> can see the flames going down) for about ten seconds, and then it will start
> again and it will keep going for another 20 seconds until it stops. There
> are no error messages in the screen, just the temperature as always...
> Everything else seems normal.
>
> Could it be that some air has gone into the system? Is there anything I can
> try to solve the problem before I call in a Vokera engineer?
>
> Thanks for your help
>
> Mario
>
>
Make sure you've bled all the air out. Check every radiator starting with the highest and work down. Also check the air bleeder on the boiler pipework. This should be on a high spot of the pipework next to the boiler or even on the boiler itself.