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1 pipe steam system question

alecs
alecs Member Posts: 10
So now I have these two Gorton D vents on the two worst radiators, one is on each branch of the steam system. The locomotive noise that I described in my last post is actually air going back into one of the gorton vents after the T-stat is satisfied.

I think it might be the Gorton vent is now the easiest point of entry for the air, and that the one vent is doing the job of the other two radiator vents on this branch. Should I put Gorton vents on the other radiators to solve the prob? Or will they end up whooshing too? There's not any noise that I have heard yet on the other gorton vent, maybe the one is defective?

Also, regarding advice to install vent in piping system, the last 10 or so feet of the piping is hidden in the wall and floor. Can I install a vent in a horiz. pipe? does that make sense?

Thanks!

Comments

  • alecs
    alecs Member Posts: 10
    1 pipe steam questions

    I have a 1-pipe steam system with a new Burnham IN-4 boiler. The boiler was installed in September, replacing an old converted coal-fired unit that was probably 80 years old. The gas conversion, at least, was done in 1963.

    One of the changes to the system has been that the new boiler can now make steam pressure, where the old boiler could fire all day and never raise the pressure above 1/2 psi or so. I need a recommendation on a bullet-proof air vent. The air vents from Home Depot seem to work OK, but tend to fail often. When they fail, they will burble steam and water, hissing and spitting all the time. I also tried some Vent-Rite vents that I got from a plumbing supply house. These seem to work better, but still have failed in some cases. (The HD vents were adjustable, the Vent Rites were fixed rate).

    One fix that sort of solved the vent problem was to set the pressuretrol really low, so that it cuts out around 2 psi. But this then means that the boiler short-cycles. It will satisfy the pressuretrol, cut out, and then restart again in a matter of a few minutes. Recently with the really cold weather, I turned the pressure back up to around 5 psi to see if I could get more heat out of the system. (I had some windows open at night because of some polyurethane work being done downstairs) This worked, but now the air vents are leaking again and I need to add water to the boiler too frequently.

    I suspect that part of the problem is that the boiler is oversized relative to the piping and radiator load. The benefit is that everything comes up to temperature quickly, but I'd also like to have the system run more steady state without cycling. Also, I think the overzealous steam production might cause too high a steam velocity in the system, causing the air vents to clog.

    Is there a way to adjust the firing rate of the boiler? I have two methods in mind - adjusting the gas pressure regulator, and resizing the jets in the burner manifold. However, I have not tried either of these - the regulator does not seem to have an easy adjustment and I need a source of new pipe plugs to play around with the jetting.

    So here are the questions:

    1)What's the best air vent? Can I use a high volume vent to reduce clogging?

    2)What's the right pressuretrol cut out and differential setting?

    3)How do I adjust the firing rate of the boiler?

    Thanks for reading this long-winded post, I appreciate any help and suggestions.

    Alec S
  • scrook_2
    scrook_2 Member Posts: 610
    lower the pressure...

    2 psi absolute max, 1.5 psi max would be better. Higher pressures will mess up the vents and waste fuel pressurizing the steam. Essentially all the heat comes from the steam recondensing to liquid, heating the steam a few degrees hotter by pressurizing the steam more will have only a miniscule effect on radiator output.

    Try Gorton vents: http://www.gorton-valve.com

    Hoffmann also makes fixed and adjustable vents: http://www.hoffmanspecialty.com/products.htm


    Faster vents will cause the radiators to heat up all across quicker, but too fast and the room temps may overshoot in mild weather.

    How are the main vents working? Are the radiator vents trying to do all the work because the main vents are clogged or missing?
    1.5 psi cutout and 1psi diff for 0.5 psi cutin should be good. Better to cycle than to run the pressure up.

    Contact the boiler mfg for recommended downfire procedure (if any!) and maximum amount permitted. You (or whoever you hire) will need a combustion analyser too to set it up right, assuming it is downfireable.

    How's it run? Quiet? Stable waterline? Clean water?
  • alecs
    alecs Member Posts: 10
    pressure

    Scrook, thanks for the info.
    The pressuretrol minimum marking on the gage is 2 psi, max is 15 psi. I will try to set it back to the lower range and see how that goes. I agree that you get most of your btus from the condensation, and superheating a few degrees does not do much for you.

    The water is fairly clean, the sight glass level fluctuates by maybe 1/2" when it's running. There are no odd noises from the system.

    The main air vent was replaced with high capacity VentRite models, and they seem to be doing their thing. The main vent is on a 12"? nipple at the end of the condensate return line, close to the boiler. The contractor explained that would help vent the main supply line as well as the condensate line. The radiators that seem to have the most trouble are the furthest from the mains, which makes sense.

    Thanks for the links to the two valve companies. Any thoughts on distributors in the Massachusetts area?

    Alec
  • Steamhead
    Steamhead Member Posts: 16,723
    Vent-Rite main vents

    are rather small. Gorton makes bigger ones which I find very useful. You want the mains to fill with steam in about a minute, measured from when the boiler starts sending steam into the pipes.

    Measure the length and diameter of your steam mains and tell us which Vent-Rite is on them. We can tell you if they're sized properly.

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  • alecs
    alecs Member Posts: 10
    model 35

    The main air vent is a Vent Rite 35. From the boiler, there is a 2" main totaling about 20 feet long. At the end of the main, it returns in a 1" condensate line (not buried). There is a tee at the end of the condensate line, one side going down to the boiler, the other with the 12" nipple up to the vent. I can hear air escaping from the vent when the boiler starts (or when I drain it, I can hear air being let into the system). I have not seen any leaks from the main vent.

    While we're at it, I was hoping to get a recommendation on the venting for my most troublesome radiator. Starting at the end of the 2" main, there is a 1.5" branch that's a total of about 25', which then tees into two lines 1.25" each, say 5' long, serving radiators in the dining room and living room. The dining room is a 7-section radiator, the living room is a 10-section. These radiators have two relatively thick vertical lengths per section. The 10-section is more troublesome than the 7 section. The thermostat is in the living room, but there's just an open doorway between dining and living rooms. What type and size of vent(s) for these radiators?

    Thanks for your help!
  • Mad Dog
    Mad Dog Member Posts: 2,595
    Gorton! Gorton! Gorton!

    Got it? They make great fish sticks too...Mad Dog

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  • alecs
    alecs Member Posts: 10
    which model gorton

    I looked at the Gorton website. They talk about a model 65 radiator vent, but when you go to the page on selecting the right air vent for your application, you get all kinds of choices. http://www.gorton-valves.com/specify.htm
    Are the 4, 5, 6, and C and D models all different variations of the model 65? Or am I missing something? And where can I find these in Massachusetts? FW Webb? Should I replace the main vent too? Or just the radiator vents?
  • alecs
    alecs Member Posts: 10
    steam radiator or a locomotive?

    So I went to the Arlex plumbing supply store, picked up two Gorton "Model D" vapor equalizers, and installed them on the two worst radiators.

    I was afraid these might be too fast, but was not expecting the sound of a steam locomotive leaving the depot this morning around 5:30 when the setback thermostat clicked to the daytime setting. Are they all this loud? What should I try next?
  • Mad Dog
    Mad Dog Member Posts: 2,595
    Definitely Gorton main vent

    at the least a #1 , but a #2 is more betterer.....I like "D" s on hard to heat rads. MD

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  • Steamhead
    Steamhead Member Posts: 16,723
    Use a Gorton #1 on the steam main

    and try one of those "D" vents at the end of the long pipe to the two slow radiators. Drill and tap for a 1/8" pipe-thread hole at some convenient point near the end of that long runout. Then you can use ordinary vents on the radiators.

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  • Brian (Tankless)
    Brian (Tankless) Member Posts: 340
    1 pipe steam

    There also seems to be another issue with your burner short cycling. Your boiler could be putting out to many btu's for your system. The btu's should be sized for what your system can handle otherwise the system will short cycle.
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