radiators wont heat up..

[goofy gorilla]

rad hi guys...ive got a biasi combi boiler model no prisma 24se model,,,had it for a good few years, never had any trouble with it, im assuming its 24000 btu...anyway, just had kitchen/bathroom/study extension done...ive added a towel rad in the new bathroom and a new rad in the study...everything worked fine.......until now, i just added another small rad in the old kitchen which is now a dining room, now all the rads heat up fine except the towel rad and the rad in the study....all the connections are fine, no leaks, bled all the radiators etc.....they just stay cold....im guessing that my boiler is not powerfull enough to heat up all the rads in the house, previoulsy i had 10 which was fine, but i think adding this 11th rad in the dining room finally broke the camels back........any ideas guys...ta

 

[seco services]

probably airlock pipework.
shut the others down till that one heats then re-set the others back to where they where before you shut them.

 

[goofy gorilla]

probably airlock pipework.
shut the others down till that one heats then re-set the others back to where they where before you shut them.

cheers mate...seems to be working.....i went all round the house and shut down every rad from both sides inlet and outlet....the two rads with the problems heated up fine... .....do i still need to go and bleed all the rads again ?
i also noticed that when i shut down all the other rads, my boiler went off and on about 3 or 4 times before it stayed on ?.....is that a concern ?...ta

 

[seco services]

once you re-open the others back up it will all run ok you can bleed if needed