Gassy smell when bleeding rads

Anyone can add inhibitor, The gassy smell is the result of oxygen entering into the system, the result is hydrogen is produced and that is the smell, and it should be stopped first, if you haven't got a lid on the feed and expansion tank (the small one in the loft) then get it covered now, a piece of board covered with plastic will do. Then best thing would be to drain the system with boiler turned off and cold feed to tank stopped. see how dirty water is when you drain it, undo upstairs rad bleed nipples first then downstairs last. Then refill and drain until water is clear, then refill with all bleed nipples closed and before tank refills add a container of inhibitor.   If you have got a lid on the tank is the water in the tank hot? If so you need to change the plumbing in the airing cupboard since it is over pumping into the tank.

 

Good luck.

 

corrosion basically. if your header tank if full of crud dont drain it through your system, drain it using a wet and dry vac and clean it out with some ppe on. if its thick of crud you could cause a blockage.

I agree with peter that the system may have been installed poorly in the airing cupboard.