I have never owned a pressurised heating system.
I am trying talk a relative (100 miles away and not very practical) through bleeding radiators. (He has described to me radiators hot at the bottom and cold at the top).
If he has a pressurised system is it near enough certain that it will have to be re pressurised after bleeding?
I have found videos on YouTube showing how to do both, but whilst there only seems to be one type of radiator bleed device so far I have found 3 different ways of pressurising a system depending on the installation (plumbed in hard, with a normally disconnected filling tube and with some WB key). No doubt his will be a 4th way.
Having watched the videos he is willing to try bleeding but to avoid call out costs intends to live with it as is if it will need to be re-pressurised.
I will not be in the area until Christmas to do it for him.