High point sealed central heating system

[Fallout]

Would it be best to install a auto air vent at the high point on a sealed central heating system. Or will all the air just eventually make its way to the top off the radiators to bleed out. A sealed central heating system shouldn't air lock on filling?

 

[Johntheo5]

Without a doubt, yes, IMO, I would install a isolating lever valve before it though to facilitate the AAV cleaning or replacement without having to drain down the system.