Air in Central System

[Exdaddy]

I replaced a radiator then refilled the system and bled the radiators. I am getting a lot of noise, particularly around the boiler area and guess I have air in the system.

I have tried bleeding the radiators and the vent valve, but no air escapes. I have also turned the pump up to its highest setting, which mostly reduces the noise, but has not got rid of the air. Turning the pump back to No 2 makes the pipes bang loudly again.

I may not have refilled the system correctly.

If I open the system drain plug, but leave the header tank to refill, will this help to push out the airlocks?

Any other ideas, or should I drain down and refill the system from scratch? If so, any tips for doing this?

Thanks in advance

[swidders]

probably easiest to drain the system as you suggest - remember to open all the bleeding valves (no pun intended) starting from the top of the house to completely empty the system and rads.

then close these, let the expansion tank fill up and leave it open and refill with system cold, starting from the bottom of the house. don't forget the inhibitor at some stage!

[Steve the gas]

Hi,

Drain down again, after tieing ball valve up.
Refill - bleeding downstairs rads first. (untie ballvalve)

Hth

[Exdaddy]

Thanks very much for your replies, I will give it another go and take more care this time!