[an error occurred while processing this directive]
Posted by HeatPro on June 19, 2006 at 12:40:19:
In Reply to: automatic air vents posted by joe on June 19, 2006 at 11:09:43:
They work, that is why they are still made for 50 years. I've had one on my system for 25.
One problem with them is that they work by wicking action. whenn the wick dries because there is air behind them, then they release te air through the wick until water hits to swell them again. This means that the vent is ALWAYs an open source for air to get in to rust whatever ferrous (cast or steel) is inside the system. You'd do just as well or better to have the one good air vent on the air-scoop expansion-tank mount and make the rest on radiators a manual vent. As an automatic vent needs only to work for a few weeks until the excess air is out, then the feed valve and the vent closed to keep water in and air out, there is little need for many open holes to let oxygen in all year.
What happens if you have all holes closed and a leak develops? No place for air to get in - very little leakage and a slow leak-dwon.
What happens if you have lots of little holes and a leak develops? - quick leakout.