Boiler making banging noises after draining/refilling system

[sha256]

Hi Guys

I had to drain down my system to do some joints and fit in a new radiator. All went swimmingly. I refilled the system and drained the air from the rads which went fine. But there is a problem with the boiler, every time it tries to heat the water the boiler makes a banging noise. I suspect air somewhere in the boiler itself, any advice in this regards would be much appreciated.

I have a Bosch 24i greenstar combi boiler that was installed under a year ago.

 

[Dotty]

You need a gsr in to vent the boiler. Ridiculous I know but it's illegal to remove the case on that unless you are gsr.