Missing traps?

Cheeze-Tech · April 2017

Ran across a 2 pipe steam system today that I could not find a trap at the radiators. The house was built in 1911. The radiators I looked at have a 3/4 pipe with a hand valve feeding the top of the radiator and a 1/2 pipe coming out the opposite side on the bottom. Could there be a group of rads on one trap?

Steamhead · April 2017

Nope. This is an Orifice Vapor system. The hand valves have (or should have) orifices or shutters in them that restrict the flow of steam. If the pressure is kept low, the steam will only fill 80-90% of each radiator, and it will never reach the dry return.

Vent the heck out of this system and install a Vaporstat if it doesn't have one.

Post some pics, especially of the hand valves (assuming they are original). There were several Orifice systems marketed during the Vapor Era, and pics should help us ID that one.

Cheeze-Tech · April 2017

I didn't take any photos of the rads. The valves look just like most other ones I've seen. 90* with a big black knob. If I get back there I'll snap radiator photos. Vaporstat? Here are photos of the boiler though. Any thoughts as to age? I see remains of an oil line.

Steamhead · April 2017

A "snowman" in a metal suit.

That type of boiler was about 40% efficient on oil, according to one of my Dead Men's books, and with that non-flame-retention Midco E20 burner it's probably about the same on gas. That thing has earned its retirement.

I see two very old vents in the piping to the right of the boiler in the first pic. Those are undoubtedly too small for the system to vent quickly. You should replace them with Gorton #2 vents, since these vents will close against water whereas the B&J Big Mouth vents will not.

The pressure control looks like a Pressuretrol, not a Vaporstat.

Most times radiators on this type of system had valves with lever handles, but a few such as ADSCO had black knobs. Pics will tell, especially if you can get any names or trademarks on them. If the valves have been replaced with ones that don't have orifices, you can get disc orifices and drill them to size.

Where is this job located?