2pipe steam no traps

jonny88

hi, i looked at a job the other day.steam heat.system is banging real bad.only two floors of heat.it is a two pipe system with no traps.the only wet return is about 4feet in the boiler room.the rest of the return is dry but from what i could see without breaking walls apart was that the dry return seemed to be both feed and return for the only exposed rad i could see.contractor said the feed does a loop in the basement with no tees on it.at the end of the basement it elbows down forming the dry return which in turn feeds rads and accepts return.am i way of base here.

nicholas bonham-carter

Venting?

How is the air getting out?

When there are no traps, it would probably indicate a vapor system, which runs at very low pressure (2 ounces). When the pressure is that low, then the air has to escape with very little resistance or back-pressure.

Over the years, an over-sized boiler may have been installed, which increases the problem of short-cycling. You may not be able to much about the over-size, but you can at least enable the air to get out quickly.

Are there orifices, or metering valves on the rads?--NBC