Keep having to bleed rads in a sealed system.combi boiler.

[fabio]

Customer is having to bleed a top radiator in a combi boiler sealed system.Could this be a build up of hydrogen?would inhibitor in the system help.Many thanks

 

[SimonJohns]

Customer is having to bleed a top radiator in a combi boiler sealed system.Could this be a build up of hydrogen?would inhibitor in the system help.Many thanks

If it smells of eggs that would be a good start to find out what it may be