Uneven Heating in One Pipe Steam Boiler

Jeff_123

I purchased an older home in the spring and I am struggling with getting my one pipe steam heat system to balance. All the radiators on the first floor except one heat up just fine, but the ones on the second floor don't get hot enough(or at all). I have read a lot about needing a main line air vent, but I cannot find one. So my first question is do I need one? I replaced all the air vents on the individual radiators with new vents and it made some improvement. I insulated my the main and risers and again things improved. But now I am need some direction on what I do next. If the system runs for a significant amount of time all the radiators will heat up, but it turns off before this happens. I assume this is related to where the thermostat is and think I should move it to the second floor which is not getting the proper amount of heat. I have also considered buying adjustable or thermostatic air valves, but do not want to spend the money if it is not the answer. I live on Rochester, NY so if anyone knows any reliable professionals in the area that would be great.

Jeff_123

I bought the maid-o-mist air vents for the radiators at Home Depot. Could this be my problem?

David Nadle

They come in different sizes. If you bought all the same size that could be why the 2nd floor doesn't heat. You want them to be bigger. Maid-o-mist are sort of a knock off of Gorton vents. Gorton's website explains how you size the vents. A much better source of information is the Gill & Pajek vent sizing document for sale on this site. I think it's $10.

TRVs will help limit heating if you have oversized radiators upstairs. They won't help you if your vents are too small.

I would buy some adjustables or faster fixed aperture vents for upstairs and give that a try.

Ross_7

Main vents

You absolutely, positively need main vents. They are the key to the whole shootin' match. Based on the venting chart mentioned above. Good luck!
Ross

mark ransley

Main vents should be new, Find out what the maid o mist is equal to in a Gorton, gortons are sized 4-5-6-C-D, maid o mist might be 5? Try a few C or D gorton upstairs, if D wont help upstairs and main vents are new then you have more options. Reduce first floor venting more and increase upstairs more, A Dole adjustable ajusts from 1-10, or a Gorton 4 downstairs, and upstairs Vari Vent has the fastest vent made. Then you spend days balancing the system. Gorton 4 or a dole adjustable set near 3-4 should be a downstairs starting point. On a few bad radiators I double vent.

nicholas bonham-carter

missing vents

the "dead men" who put this system in must surely have had a main vent, and perhaps its opening was plugged up later.they are usually placed where the return is dropping down from ceiling to floor next to the boiler.
they are absolutely essensial.--nbc

Unknown

Jeff- As NBC says, on a one pipe system , you have to have main vents!

For a steam system to work you have to get the air out of the pipes so the steam can move in!

On the mains, there are vents at the end to let the air escape. These close when steam gets to them. Each main needs its own vent. You need to trace down each main and find the vent or where the vent used to be. The vents on the mains have orifices 10 to 20 times larger than the vents used on the radiators. Mains don't have to be just horizontal but can go vertical too so check if the pipe(s) going to second floor are mains as they will need a vent. (Mains service multiple radiators)

The single pipe leading directly from the main to the radiator and the radiator itself needs to be vented also. This is what the vents attached to the radiator do. If the main vents aren't present and/or working, the radiator vents try to do the both the main vent's job and their own job and since these radiator vents have a very small orifice opening they just don't do the combined job very well if at all. (An indication of this happening is it takes a very long time for the radiator to heat if it does at all)

On an old system the lack of main vents is probably due to some idiot, not knowing the vents importance, fixing a leaking vent with a pipe plug. ("There, that fixed the leak! Don't know why they put that silly thing there in the first place!)

If you don't already have them get Dan's books on steam heating. (See "A Steamy deal" at the bottom of this page)
A "must" for owners of steam heating systems and worth every penny. They're crammed full of information and are easy reading.

Steamhead (in transit)

Maid-o-Mist

uses the same sizing schedule as Gorton. But the Gorton vents are much better made. That's why Home Depot carries Maid-o-Mist instead of Gorton.

In general it's not a good idea to over-vent one-pipe steam radiators. If the vent is too big, steam will be able to rush up the riser so fast the water won't be able to drain back. This can cause banging.

We get rid of most of the air with the main vents. That way the radiator vents don't have to be so big. A brand-new main vent that's too small won't do much good.

Measure the length and diameter of each steam main and post the results here. We can tell you what you need.

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Terry in NJ

Hopefully you don't have a finished basement

I found mine hiding behind sheet rock. I spent a lot of time looking down through a mirror from the dropped ceiling to locate mine. Look for things that look like bullets, stopwatches, clocks or upside down conetop beer cans.