Noisy central heating system

[Meggalar]

Hi,
I recently drained down the central heating system and refilled including inhibitor. However since doing this a few weeks ago there seems to be lots of air in the pipework/hot water cylinder which is now very noisy.
I've been bleeding the radiators ever since but this doesn't seem to have made much difference.

I've had a similar problem before and an engineer removed the air by stopping the pump and open some type of bleed valve which is fairly high on the pipework above the pump.

Could someone please advise me what I should do to remove the air in the system?

Thanks
Richard

 

[Armo74]

You need to ensure that all bleed valves have been vented properly even the pump. Bleed the one at the highest point like someone did before.