Cold Radiators

Scott Larabee

First of all, those pressures are WAY too high for a residential steam system!

Are the radiators that aren't heating now the same ones that were closed when the pressure hit 10 lbs? If so, it is possible that the valves to the radiators have come apart. That would allow enough steam to pass through to get the pipes hot, but not the radiators. The vents on the radiators could also not be working properly.

Generally steam systems run on about 1 1/2 lbs of pressure. Most operate at less than 1 lb!

Scott

Just saw that Frank beat me to it while I was typing!

John_141

One Pipe Steam System

I have an old colonial that has an old oil furnace converted to gas running a single pipe steam system with 2 mains. I had the system serviced a few eeeks ago, cleaned the pigtail, the pressuretrol and the burner, replaced the thermocoupler, drained the system twice and vacumed out the furnace etc. Since then its been working well, the one radiator that is the furthest from the system that wouldnt heat last year now gets heat pretty quickly. There are 3 radiators though that are cold and not getting anything,and are at varrying distances from the burner; 2 are ont he main floor one story up from the furnace and one is on the 2nd floor. TOnight i checked them and they are all open, the vents are clear and their feed pipes from the basement are hot, yet the radiators are cold...any ideas? the pressure runs between 4 and 6psi, the highest i saw it was 10, but that was because a few radiators were closed. i have 3/4" vents on the mains.

Steamhead (in transit)

Pressure is too high

and it's closing the vents. Crank it down and I'll bet the problem goes away.


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Dean_7

pressure

I'm just a homeowner but I have a one pipe steam system. Listen to both steamhead and Scott they're right. Second if you want to do a real favor for yourself and your system replace the pressuretrol with a vaporstat. I did at steamhead's suggestion and now my system runs at about 8 ounces of pressure and absolutely perfect. That's how these systems were originally designed, low pressure. Also if you want to know more buy Dan's books "We Got Steam Heat" and "The Lost Art of Steam Heating" both are invaluable for anyone who has a steam system.

John_141

First off, thank you for responding and for the help.

Now, how do you lower the pressure? this is an old cast iron boiler that was converted from oil to gas.
here's an odd thing as well, AFTER i wrote that post last night, my 4 year old had me up until the wee hours. It was cold upstairs so i turned the heat up and i noticed that all the radiators were working fine, they all got heat. I did not venture to the basement to look at the pressure guage however. In the upstairs bedrooms all radiators have adjustable vents by heat-timer that i installed last winter. the rest of the vents are mostly maid-o-mist style fixed vents. Thanks again

Steamhead (in transit)

There is a control on the boiler

whose job it is to limit the pressure. Usually it's a small gray box. Take a pic of your boiler and post it here, and we'll point it out to you and tell you how to adjust it.

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John_141

control

I looked over the boiler and i dont see anything...the only box on the boiler is the one that is connected to the pigtail...is this the box you are referringto?

on another note, i checked the booiler again yesterday and the pressure seems to have stabilized at just under 5 on the guage, which is where it was all last year. Also, now all the radiators are getting hot, so perhaps the night that the radiators werent ht the system wasn't on long enough...not sure exactly. anyway, thaks again for the hlep...this is a GREAT site...i'vce learned so much here