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Insulating near-boiler piping

I've got a system that is adequate, but only barely adequate, to feed the radiation load.

I'm thinking it would improve things if I insulated as much steam pipe as possible.

All the near-boiler piping, headers, etc. is large-diameter pipe with loads of tees, elbows, etc.

What's the right way to insulate these pipes and fittings? 


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    barely adequate!

    how do you know that your system is barely adequate?

    definitely insulate. do a search here for insulation to find various supplier recommendations, or you may have a local supplier. the straight pipes are the most important, and you can do the fittings later. if cost is an issue, fiberglass batts can be wrapped and taped around as a temporary solution.

    while you are spending quality time with your boiler, check the main [not rad] venting. extremely capacious venting will get the air out, and the steam up to your radiators sooner, especially if your pressure is as low as possible. a good low-pressure gauge will show you what your pressure is [gaugestore.com 0-2 psi].--nbc
  • Patrick_North
    Patrick_North Member Posts: 249
    Turn out the lights and it looks the same...

    After shelling out $$$$ for a new steamer this year I stared at the mess of 4" tees, elbows, and such and decided some good ol' 15"X3 1/2" rolls of the pink stuff would work just fine, thank you very much.

    I was loathe to spend the money on "legitimate" pipe fitting insulation/jackets because of cost and because the header will need to be redone at some point, anyway (it's a long story, Chris) but I'll tell you what- it works great and was a piece of cake to install. The rest of my mains have 1" formed fiberglass insulation and this seems barely adequate. But with my (butt ugly, pink) header you can hold your hand on it and not know if it's steaming. And yes, this is unfaced- no craft paper.

    When I've finally fixed my header, maybe I'll dress it up right, but I don't know. I'm sure I could improve the aesthetics, but I'm not sure I'd improve the R value- and at what cost?

    Good luck,

  • tmw
    tmw Member Posts: 56
    edited January 2010
    how is it attached to the piping?

    Did you tape it every few inches or so? What sort of tape? This sounds like a good way to insulate my fittings.
  • tmw
    tmw Member Posts: 56

    This question was already answered..
  • chris_69
    chris_69 Member Posts: 29
    How I know it's just barely adequate?

    I know it's just barely adequate for two reasons. 

    First, if I add up the radiation and look at I, B, and R numbers the boiler capacity is right where it ought to be. Ordinarily that would be perferct,  but there is an unusually long copper (ugh) main, tucked into a place that is hard to insulate. That's not an awful thing, because the heat radiated and convected off that main heats a part of the house that needs to be heated, but it means there's more effective radiation than the total of the radiators plus a typical pickup factor would suggest,

    Yes, there's a honking big vent at the end of that main. I don't know what size or brand it is (it's up in an awkward place and I can barely see it) but it's bigger than my fist and I can hear air come whooshing out of it as the boiler fires.

    Secondly, even if I force the boiler to stay on indefinitely (by setting the thermostat to 100, for example), the boiler pressure doesn't lift off the zero peg... That would normally be perfect, except I can tell that the radiators are condensing steam faster than the boiler can make it, because even full-on for a long time, the radiators don't heat all the way across (which is also OK, because the house, like so many 19th century houses that were later insulated, is grossly over-radiated)

    So I figure that the boiler just misses carrying the full load by a hair, and insulating another 20 feet of 3" pipe ought to just put it into perfect balance. I was trying to figure out how to do it without going broke buying fittings for all those 3" tees, elbows, etc. near the boiler.
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