Posted by Harold Kestenholz - Hydronic Network on November 01, 2001 at 08:32:53:
In Reply to: Radiator Valves position posted by David A. Burya on October 31, 2001 at 09:45:09:
You need a vent six inches from the opposite end of the valve. It is the speed of the air venting that balances the heat in radiators; although the heating and cooling speed of fin-tube will not coordinate with cast-iron. A partially-closed valve in a steam system can trap water in the radiation to bang against the ends. If there is no vent in a radiator and the valve is successfully closed while there is steam inside, cooling steam can go into vacuum and atmospheric pressure can crush the tubing. Fortunately, many one-pipe valves have a bleed cut in the seat. You can regulate heat ouput from fin-tube by placing 1-foot long aluminum sheets over the top of the fins to adjust how much air can go through the fins remaining exposed to air flow.