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Venting a Mess

Ryan_10 Member Posts: 26

Thanks for the confirmation. I agree venting the dry return for the main is a waste, but that will have to stay for now. Me, saws and drills and a 1.5' tall crawlspace in winter aren't going to mix unless something rusts through.

I'll tap in a vent on the end of the submain, which may do wonders, but leaving that end cold radiator wide open doesn't really seem to do that much for getting steam over there.

I had one thought that if this doesn't work well enough (particularly seeing as I may be tacking on [moving one, actually] another radiator because some dimwit left a room totally unheated) is it feasible to tap in near the header, and add a "supplemental" say 1" parallel flow pipe running ~14' over to that submain to help out? I put the whole mess into Paintshop to give an idea of the whole setup. This might actually be pretty easy to do-- no more difficult than tapping in for a vent, really.

Right now I'm not heating most of the upstairs, so the risers can waitfor now. Thanks again.


  • Ryan_9
    Ryan_9 Member Posts: 6
    My piping is a disaster...

    I'm hoping someone will have a decent suggestion on what to do. I apologize for the length of this. My house was built in 1890, and the single pipe steam heat I suspect went in sometime after. The majority of it is in 1.5' to 2.5' tall crawlspace. It took me three hours crawling it dirt and filth to map this mess out. Fun.

    Here's the problem: A 2200sqft house with one 18' (parallel flow) 2.5" (I think) main off the header and a 1-5/8" 16' dry return for the whole mess. That has a functional Dole #4.

    The problem: ~130' of "other": sub mains (see below) and minimains (x2: 11' & 21') and a sub-dry return (and 20+ ft wet), not counting the risers to upstairs radiators, which adds another 40-50'.

    The 2.5" main has a sub-main coming off it after 14 feet, half parallel flow and half counter (transitions where it goes over the brick wall from CS back into BM) In total this thing is about 43' of 2" pipe going down to 1-5/8" at some point, before hanging a "U" into a 1"OD pipe 16' long, which then drops into a 20' or so wet return. Before it drops, there is a vent with a Dole 1A set to "10", long dead. Wide open pipe, it takes about 20 minutes to get steam here.

    My basic question is this: Should I take a somewhat unorthodox approach here and put a really small vent on the actual main and a large vent on the submain in a half-baked attempt to even this mess out? Drill and tap another vent at the end of the submain before it becomes a dry return?

    I've already figured out I'll have to list with much of the hissing because many of the rads are on 1-5/8" or 1-3/4" runouts that are anywhere from 10' long to 15' downstairs, and 10' to 25' long upstairs, and in the crawlspace.

    Any help appreciated. Thanks!

  • rick_33
    rick_33 Member Posts: 20

    Is your house heating and is it one pipe or two pipe system or combination .Is the system has old as the house .
  • Ahh yes- those are fun

    Before I answer this, are there any more radiator takeoffs from the "Main" main after the sub-main tees off of it?

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  • Bob W._3
    Bob W._3 Member Posts: 561

    rick, he mentioned it was single pipe steam.
  • Ryan_10
    Ryan_10 Member Posts: 26
    Yes, there are takeoffs...

    I don't have the diagram sitting in from of me at the moment, but there definitely are takeoffs. I believe there is one 1-5/8"OD about 10' long to a downstairs radiator and another takeoff the same diameter 13' or so, plus ~11' of 1-??" vertial riser to an upstairs radiator. Both tee directly off the end of the main. The end of the main essentially has three tees stacked: Those two, plus the dry return. The submain tees off about 5' in front of this. Thanks in advance for any suggestions.
  • Then your \"unorthodox\" idea is correct

    I just did essentially the same thing on a system that had been added to at some point.

    The longest run to vent is the part of the "Main" main up to the tee for the sub-main, and the sub-main itself (that is the only sub-main, right?) . Vent this with two Gorton #2 vents placed at the end of the sub-main, or place them on the dry return from the sub-main as it exits the crawlspace if this method is considerably easier. Oh yes, make sure any vents on that dry return tap into the return at least 18 inches above the boiler's waterline. If that means you can't put vents there, so be it- put them in the crawlspace.

    The remaining portion of the "Main" main can be vented with the existing Dole #4 or a Hoffman #4A. All this vent has to do is prevent the venting of air in the main thru the radiators running off this portion. The best place for this vent is at the end of the "Main" main rather than the end of the dry return. Why fill the return with steam if you don't need to?

    Do this much and see how the system reacts. You may or may not need to vent your risers.

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  • Ryan_10
    Ryan_10 Member Posts: 26
    Oh, it heats...

    Plenty of capacity and heat, although all the Dole 1As snap loud as heck, and constantly load up with water and buzz like the world's crappiest saxophonist. Pieces of crap, and next on my list.

    System appears mostly as old as the house. At some point, the submain *may* have been extended about 10 feet c. 1930s, judging from the newspapers that were wrapped around the pipe insulator. (Beats me).

    I might just end up having to replumb with a proper second main, because at some point I have to make that submain another 6' long to add a radiator to an unheated porch someone "housed" up and never bothered to add heat to.

    Of course, if I can make this work without having to replumb, I'd like to do that.. I've got enough new house blues right now.

    On the funny note: I though that porch was walled off from the rest of the basement and that the old guy had just put some PINK against the wall and covered that with chipboard. Turns out the chipboard *IS* the wall, and the PINK sticking out the top was just 6" of insulation to stop the draft. This basement has a gaping 6.5'x11' hole to the outside basically covered by chipboard and the boards around the bottom of the porch, and before I insulated the header piping and the chunk of the submain in the basement, it was still staying a toasty 80 degrees or so. Cute. Oh, and the attic didn't have a stitch of insulation in it. =)
  • If the 1-1/2\" pipe

    has 150 square feet EDR or less, the 2" has 386 or less and the 2-1/2" has 635 or less with the new rad added, you won't need to run another main.

    Close in the area under the porch and insulate the porch roof if there isn't a room above it, and it won't need nearly as much heat.

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  • You have so little venting now

    that it's no wonder it takes so long for the steam to get that far. Those Gorton #2 vents will work wonders.

    The determining factor for adding radiation is the size of the pipe, and if it's parallel-flow or counter-flow. But if the sub-main isn't big enough for added radiation, cutting it off at about the point where you have a proposed helper main connection and piping a new main for that section would work fine. That sub-main does look kind of long compared to the "Main" main.....

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  • Ryan_9
    Ryan_9 Member Posts: 6
    Thanks for all the help, I'll go ahead..

    With trying to get that submain vented this week whether I have to drill and tap or add a tee or what.

    I added up all of the pipe volumes and I'm under 1 sqft for the main and submain, excluding returns. .95 sq ft to be exact. The Gortons are $50/ea and Varivalves only $18.00, so I may just try Varivalves for now which will provide 1.32CFM--more than enough from what I've been able to gather by reading the archives and the Gill/Pajek charts. Heat-Timer's measurements claim even better figures that about match the #2 at half an ounce (1"WC). Maybe in the future I'll spring the $100 for a pair of Gortons with a float, just in case. The extra for now will let me replace those crappy, noisy, buzzing Doles.

    I'll post an update later with how this works out.
  • Use the Gortons

    All those bends, twists and tees slow down the steam flow. The Gortons will compensate for this.

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  • Dave_4
    Dave_4 Member Posts: 1,405
    I was forgetting..

    about the turbulence and friction created in those old pipes and all the bends. Thanks for heads up. I'm new to this, forgive me ignorance. Obviously when I have a couple inches of pressure at the boiler I won't have that at the end of a 60 foot run run starting with a 2" pipe and narrowing to 1-1/2" then 1-1/4". It's going to need a gaping hole to get the air out when the steam starts.

    Of course, that assumes the charts here are correct. I have no reason to doubt them personally, but Heat-Timer does say otherwise. Their data shows their vents clear as much as a #2 at 1/2 an ounce. They've got a PDF file claiming to have measured lab results with a #2, a Hoffman 75 and #4, as well as the whole line of Gorton and Hoffman radiator vents at 1" (or ~1/2oz). It's just a bar chart, so that's a bit of a pain to guess at. I'll try to give them a call and see if they have the study, done by the Center for Energy and Environemtn, from what I can tell, possibly sometime in the mid-80s.

    As a radiator vent they claim a rate of ~.72CFM at 1/2 ounce, and near 1.0CFM as a mains vent. I'm assuming the difference must be angle vs straight pattern and turbulence or constriction problems from the narrow diameter bend, which does jive with the #s from here. A Gorton D is .44, a 1A .18, a 75 .6, a #2 just a touch over the Varivalve. It's the only other comparison I've see besides the chart here, but the web isn't exactly a great steam heating resource compared to what many guys here have in books, I'm sure, and practical experience. Have you (or anyone else) ever tried swapping on a straight pattern Varivalve in place of a #2 and seeing if there is a noticeable difference? Practical experience always wins, hands down.

    Sorry for the overlong rambling.. Non-reading totally excused. =)
  • Heat-Timer

    wants you to buy their vents. Gerry and Steve are doing their measurements solely to collect and provide accurate information. I'll go with their charts over those of any manufacturer. On that basis, the Gorton #2 rules.

    Also, the Heat-Timer vents don't have floats in them to close the vents against water, but the Gortons do. That's worth considering, even in an old crawlspace.

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  • Ryan_10
    Ryan_10 Member Posts: 26
    I did a few calculations..

    for the EDR yesterday. 3 yr old replacement boiler of course 25% oversized. Grumble. I'm learning way too much from this forum and the resources here.

    But the boiler isn't the issue here so much. The main is just barely large enough. The 1-1/2" submain isn't. It has 200sqft EDR connected, with 140EDR *COUNTERFLOW*, and some of that possibly on 1-1/4" pipe. The remaining 60sqft is on parallel flow and definitely 1-1/4". I'm not sure where the pipe size changes.

    From the numbers you provide, this submain is servicing far too much EDR, particularly when derated to 75 or 80 EDR per some of your earlier posts (a few years ago) and Burnham's guide for the 27' long counterflow portion (unless there is a lot of pitch on the pipe, which I didn't measure.) Unless I'm misunderstanding this, its no small wonder I can't hardly get steam over there even with two 1/8" radiator vents uncorked, plus a third 1/8" uncorked on the dry return for this mess.

    I'm sure the Gorton's will help a good deal, but this situation would still seem to leave a lot to be desired from a design standpoint. Thanks again for all your help.

    Incidentally, I called Heat-Timer about that study and supposedly they should have it ("If it's referenced in our literature, we should have it and be able to give you a copy."). They say they'll fax it. I'm a data nut. Can't help it. I'll post it here if it actually comes.
  • That sub-main

    was probably added to over the years and no one bothered to check its capacity. You have the right plan to solve the problem by splitting it up. It'll be a lot of work but worth it. Start a completely new main from the boiler if you can, that will unload the Main main a bit.

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