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"how tight" for circulator flanges?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by pybyr, Jan 12, 2009.

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  1. pybyr

    pybyr Minister of Fire

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    I am in the home stretch of the plumbing for at least the initial incarnation of my system (w/o storage and with controls only sufficient to get this thing up and rolling for the fast-coming below zero weather).

    and I sometimes, some say, worry too much about details- but I prefer to try to get things right.

    on the circulator flanges, how tight is proper when tightening down the bolts?

    obviously, I want the gaskets to compress enough that they meet and fill the little irregularities in the metal surfaces, and that they can respond to expansion and contraction with changing temperatures - and I don't want them so tight that they are crushed beyond usefulness

    I think I have my own instinct of what that concept adds up to in practice, but would welcome others' suggestions as to how you arrive at "properly tight" but not overtightened.

    Thanks

    Trevor

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  2. Dave T

    Dave T New Member

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    The best part about flanges is if they are a little loose a little tighten is all it takes and they will seal even with some water dripping I figure a little loose with flanges then tighten to suit,hope you didn't want a scientific answer if you do I am sure others will jump in ..Dave
  3. stee6043

    stee6043 Minister of Fire

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    I used a standard open end wrench on mine. Got them about 80% as tight as I could go and no leaks...
  4. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    There's no specific torque spec, because there are so many different flange designs, and gasket materials available.

    The first rule is not to invite your buddy Torqulese to tighten them, because cast iron or cast brass will snap pretty easily.

    As has been said, if it's a little loose, you can always tighten it down a bit more.

    Joe
  5. pybyr

    pybyr Minister of Fire

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    great- thanks all-
  6. heaterman

    heaterman Minister of Fire

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    Basic rules of thumb:

    Don't bottom them out to where metal meets metal, just snug will usually do on flanges of decent quality like Webstone (my 1st choice) or B&G;.

    As you tighten them down, do it equally. A couple turns on one side and then a couple on the other. Try to keep the circ and the flange square with each other.
  7. in hot water

    in hot water New Member

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    flat or ring style.

    The ring gaskets, supplied with the circ, don't need much torque. the thin, flat gaskets tend to need more tightness. a 6" crescent is plenty of "tool" I have a duel box wrench 5/8 and 11/16 about 4" long that works great. It's easy enough to add a bit of tightness, start out with just snug.

    Proper alignment is important. Use plated bolts incase they need to be disassembled someday.

    hr
  8. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    I'm still waiting for one of the maufacturers to step up and offer flanges with stainless bolts...

    Joe
  9. chuck172

    chuck172 Minister of Fire

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    Best thing to do is coat the bolt threads with "never sieze". Fantastic stuff, lubricates the threads and you'll be able to back off the nuts easily 20 years down the road.
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