bleeding of radiators

[nello]

has anybody had experience of bleeding radiators, but get a bad smell of gas which i believe is a build up of methane which you could actually light with a lighter. Never had this before until today when bleeding rads for a friend, any suggestions on why this happens and how to resolve it would be greatly accepted.
thanks kev.

 

[namsag]

It is hydrogen and is very common, inhibitor should stop it

 

[nello]

thanks i shall pass message on probably do job myself, did,nt know it was hydrogen