I have just converted my system from an open vented one to a sealed system using a Wyatt expansion tank (it's fitted with the gauge on the top) However I am still having a problem with air in 3 of my 5 rads upstairs.Is this normal. I have checked for leaks and haven't found any, so am are rather baffled. Could I rectiy it with Automatic bleeder valves on the rads.
