Air bubbles in water are as common as clouds in the sky or waves on a lake. Most people take them for granted. However, those working with hydronic systems quickly learn that air in their systems is undesirable and seek ways to get rid of it.
My “attitude” on air in hydronic systems has changed over the years. I used to fear situations where air could get trapped in system piping and create problems such as loss of flow, noise and the (justified) complaints that would follow. Part of that fear was based on my inadequate understanding of how air behaves in a hydronic system.