Automatic Radiator Air Vents : Do They Work Without Side Effects?

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Doug Morford

Member
Dec 10, 2012
89
Moscow, ID
I have no doubt these do work. I have one installed on a small 10 gallon system, and it bleeds fine. The automatic bleeding function I'm sure works as well.

They work by using a pack which expands and seals when wet. When air accumulates, the pack dries and shrinks, letting air out.

My question is, do they also slowly bleed off water by evaporation through the pack? I would think they'd have to at least a little. On a larger system, this small amount of water loss would probably be fairly benign. On my small system though, I'm a little concerned about this potential downfall because as little as a gallon of loss over time would render my system non-functional because it relies primarily on gravity for flow.

Anybody have any experience with these? If nobody can smooth my ruffled feathers, I think I'm going to replace it with a regular bullet proof bleeder.

Doug
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