2 pipe steam

ed wallace

im trying to solve a problem on a 2 pipe steam system a plumber added a radiater to the system in kitchen/breakfast nook area the last 9 ft of pipe are in a crawl space the supply pipe is insulated its a 1in supply and 1/2 return radiator has a hard time heating its the last radiator on the supply pies are pitched correctly anyone have any ideas

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TGO_44

Is the main

large enough to carry the total load? If the pipe was border line to begin with the new radiator may be too much load for the main. What kind of return trap did they use, and how is it connected to the return? If you can post a little more information someone here can help.

ed wallace

the main is 2 inch black iron with 6 rads off it all piped in 1 inch black iron the returns are all 1/2 inch into 1 1/2 black iron no traps anywhere

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Unknown

Ed, how does the air get out of the returns? Since there are no traps, what keeps the steam out of the returns? Are there orifices on the radiators?

Noel

Steamhead

That's probably an Orifice Vapor system

which keeps steam out of the dry return by limiting the amount of steam going into each radiator. The other possibility is that there are special return elbows or bushings with water seals in them.

You may have an air venting problem here. All of the above systems vent air from the rads into the dry return. There should be a central air vent on the dry return somewhere near the boiler. If the vent is not there or undersized, this can cause your problem.

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Boilerpro_3

If it was an orifice system....

Maybe the orifice valves have been removed on some rads and the return is becoming pressurized. Also, you may be able to throttle some of the rads that are heating in order to convince the steam to move out further. Steam is lazy, it will always follow the pass of least resistance. Definitely follow Steamhead's advice too. If that main vent isn't right, youare going to pay alot more for fuel than necessary and be much less comfortable. I replaced an undersized vent in a vapor system once, and after that the second floor of the home heated properly for the first time in 30 to 40 years.

Boilerpro

ed wallace

all the rads have air vents and can find no traps anywhere in the house this 1 rad is a later addition all the rads have shut off valves on supply and returns i will have to disconnect a rad to see if there are orifaces installed the only main vents are on return piping just above the boiler

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Unknown

Sounds like a 2 pipe air vent system

No orifices or traps. Page 228 in Lost Art. Does the boiler make enough steam?

Is the two inch main big enough to carry that radiator and all the rest? It should carry about 648 Sq Ft or less when it is two pipe steam.

Noel

Steamhead

Also

do the rad returns drop below the boiler waterline before connecting together? If not, you can have air coming at a rad from both the supply and the return lines. Even a Gorton #D vent won't cure that!

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Bob_19

I would

try Boilerpro's idea, start at the closest load and shut them down as you move away always checking the problem radiator to see if it's getting steam. It'll give you an indication of possible load/supply issues.

Or

If you can open the return on the problem radiator to see if it starts taking steam, if it's air locked it should start getting steam.

ed wallace

when i disconnect the supply pipe to the rad the steam pants in and out in other words there is a shot of steam then its as if air is sucked back in sort of like someone breathing

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Unknown

Ouch

Steam isn't getting there. Boiler sized big enough? Pipe too small to carry it? Insulation missing? Wet or dirty steam?

I think you're onto it now, Ed.