Adjusting/Controlling Heat on Steam Radiators

I'm in a building with steam heat (one pipe system?) - free-standing radiators in all the units. We are trying to cut heating costs and at the same time get better control of the heat in individual units. Overall, the units are too hot. I've been doing a little research, and have come across "thermostatic radiator valves" and "adjustable valves". Are these the same thing? Essentially, is there a way to reduce the amount of heat a given radiator produces, and will this in turn decrease out heating costs? Sorry to sound clueless, but I'm trying to figure out how these valves work, or if I'm on the wrong track and there's some other solution!
Thanks,
E
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What air vents do you have now, If you put in an adjustable one ,Dole , the tennants will ajust them higher. Gordon makes 3 or 4 vent ranges for controling heat You have to record all temperatures and then balance your bldg. normaly the farthest away from the boiler has the largest opening and the smallest is near the boiler. You havnt said where you have to much heat, near the boiler or farthest away, You need calibrated thermometers in every apt, or an infrared to go around to each unit and start a log. Then you can figure your course of adjustment
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You can't adjust the amount of heat a radiator produces once its full of steam, but you can make the steam take longer to get there- reducing the average heat. The adjustable air vents are for that. Basically you tweak the diameter of the vent hole so the air in the radiator and steam pipe takes longer to get out, so by the time the heating cycle is done, the radiator will not have had enough time to get filled with steam.
The idea behind the vents is they're open at room temperature, the steam pushes the air in the plumbing out in front of it. Once the steam hits the vent, it closes. Inside the radiator, the steam condenses forming a vacuum relative to the plumbing, sucking more steam into the radiator. At some point, the vent may return to room temperature, whereupon it will open. If the boiler is still firing, that will allow more steam to push its way in. Otherwise, the steam in the plumbing thats condensing will have itself formed a vacuum, leading to a gentle hiss as air returns into the radiator and piping. A reasonably operating sytem will provide infrequent, quiet clicks and hisses during a heating cycle. Loud snaps, continuous hissing or water hammer are all signs of the system needing attention.
If rooms are getting too hot even with the vents turned way down and the system is pretty well balanced overall, it may be necessary to switch to smaller radiators or enclose them to reduce air circulation. Adding yet another layer of paint will also reduce output a little.
Another thing to check is your steam pressure. If this is a simple and smallish system, ensure the pressure is just a few ounces (like 3 or 4)- meaning the boiler will stop firing when the steam pressure gets over that limit. A very few ounces of steam will zip right down the mains. If the pressure is higher, the boiler will be blasting away, pushing more and more steam into the mains, but the radiators can only condense it at fixed rates, so the extra steam just sits there in the pipes waiting its turn- wasted since its not condensing in the radiators where you want it. All that extra steam can also lead to more heat than you want, since the whole system will be condensing quite a while after the thermostat cuts out the boiler.
If the steam pressure has been raised in an attempt to fix "cold" radiators, the solution is to reduce the pressure and find out why the cold radiators aren't getting enough steam- inadequate air venting, water pooling in the plumbing, unbalanced system, etc.
Theres also general stuff you can do which makes a big difference, insulate the mains, make sure all the vents are working, get the burner serviced, etc...
Gregm
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Greg in an apartment the Last thing you want are adjustable vents. Tennants always screw with them, they always want more free heat , so they can open the windows. Any system can be balanced. But it takes work.
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snipped-for-privacy@webtv.net (mark Ransley) writes:

Depends on how big the system is, doesn't it?
Gregm
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No Greg , Im not saying its easy to do or cheap on long cold runs i have double vented, also main vents on boiler and pipes go bad. Most people dont know how to balance a system ,or wont spend the time. its tedious work if its way out of wack. it took me one winter , a few hrs a week, to do one or maybe 70 hrs. . I once found a tennant removed the vent getting his apt to 80. Another old lady complained it was cold, till I came out early and her windows were open. A smoker. Point is give a tennant an adjustable vent he will mess with it , and that unbalances, cools, the next apartment.
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snipped-for-privacy@webtv.net (mark Ransley) writes:

You're right of course. As usual, I hit send before thinking... ;)
Gregm
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