Constant air in 1 rad

[malagabob]

Had a Worcester Jnr condensing boiler fitted about 6 months ago as a replacement for open vented system. I fitted a replacement but larger rad in living room and 1 same size but double panel in a bedroom.This is the one that gets air in constantly.
All other rads are original.
Have never had air problems with original system. Have checked for leaks when system cold.

 

[Whn1]

Does the air smell pretty bad?

 

[malagabob]

No cant say it does, but have not got my face close enough to smell anything. If it smells what would that tell me?

 

[kay-jay]

Move curtains out the way and try to ignite the 'air' if it lights it is hydrogen a by product of corrosion. A flush and chemical treatment will sort this.

 

[ambrosia]

have any automatic air vents been moved or if there were original AAVs have the isolation valves to them been adjusted

i dont think its hydrogen from corrosion as this takes a while to build up, i suspect air is being sucked in from some where, probably caused by bad pipe lay out which has been patched up, then what ever the patch was its been removed when the new boiler was put in