Once you realize that the only way there is condensate sub-cooling if when the condensate passes thru an air pocket and gives up heat causing the sub-cooling you know that it is very important. Air locked in the ACC reduces the available area to condense steam and therefore can affect performance. After acceptance (completing a performance test) air in the ACC if the ambient temperature is above freezing cost the plant money because you are not condensing will the full surface of the ACC. Below freezing the air pockets if left unchecked can lead to ice plugs forming which can result in rupture of tubes.
