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clanking swing check.

ch4man
ch4man Member Posts: 288
well i was into my second paragraph of my question and my laptop crashed and erased it all. hhmmmm.
ill just asked the simple question, will fill in the blanks later
what are the conditions that can cause a swing check to clank?
just did a repipe to unknucklehead a 120K slant fin.
im suspecting gravity circulation is setting up and the swing check flapper isnt heavy enough to stop it
or am i out of my mind

Comments

  • hot_rod
    hot_rod Member Posts: 18,203
    Not the best check for hydronics, should be a spring type, soft seat.

    A swing check needs a pressure differential to close and seal. When the circulator shuts off you have no differential.

    They need to be sized by flow rate, not pipe size, insufficient flow moves the gate only part way and they clang around.

    A spring or weighted flo check would be a better choice.

    Swing check can be used in hydronics when you want some flow in a no power condition to prevent overheating, wood and coal boilers for example.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,971
    Are you using a swing check instead of a flow check to try to stop gravity flow?
    steve
  • ch4man
    ch4man Member Posts: 288
    wasn my choice but it happened.
    so 2 options would be a B&G flow check. that will require some repiping.
    next choice is the easy route IF i works and that would be to replace in IFC in the grundfos 15-58.

    yeah i was there for the repipe only as help. not going to throw others under the bus but i work with a guy that loves swing checks.

    so IFC spring strong enough to stop a gravity flow?

    there was way more wrong with the original install, it all needed to be changed but i fear we left one issue we were trying to fix
  • hot_rod
    hot_rod Member Posts: 18,203
    IFC and weighted flow checks have a "pop" pressure between .35- .50 psi. That should be adequate for stopping ghost flow.

    But improper piping with multiple circulators can be another reason for checks not holding. Incorrect primary secondary for example, and in some cases you need checks on supply and return piping, you can get circulation up and down a single return for example.

    I like hydronic checks best as they are considered 100% "bubble free" protection.
    If you have a basic brass swing with no teflon seat I doubt it is sealing tight enough even if installed properly too be doing much good.

    Caleffi has a nice union hydronic specific check with a choice of connections, press, 2 pex, sweat or thread. Very easy to retrofit and service if needed.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • ch4man
    ch4man Member Posts: 288

    Are you using a swing check instead of a flow check to try to stop gravity flow?

    not exactly Steve. yes there was gravity flow however the original NBP left much to be desired.
    turn of the century high end home, gravity conversion ( 2" CI, CI rads) on one zone, zone 2 in floor pex run fed through Taco 007 zoning circ, taco mixing valve. 120K slant fin piped with 1" pipe, zone 2 connected where it was causing flow in the CI zone.

    our plan was to add a circ and repipe pri/sec with correct sized pipe. unfortunately we used swing checks instead of using circs with IFC's
    the next day the home owner now complains of clanking throughout house.
    I have not been back to confirm as the flu has invaded my body.

    so while the homeowner has only complained of noise, not temperature issues so my original question is just as i stated, "what conditions can cause a swing check to clank"
    Hot Rod gave good advise as did you. in retrospect as the main house is fed with "closely spaced tees" off the top of the boiler loop i now believe because the boiler loop will be quite hot as zone 2 is a small load the hot boiler loop gives a perfect place to set up gravity flow up the supply tee past the swing check and back down the return afer the CO rads cool the water only to drop back the return tee

    so weighted flow check will requires repiping, replace circ with one that has a built in IFC is easy.
    will the spring in a grundfus 15-58 fc be strong enough to hold back ghost flow should my theory be correct?
  • ch4man
    ch4man Member Posts: 288
    hot_rod said:

    IFC and weighted flow checks have a "pop" pressure between .35- .50 psi. That should be adequate for stopping ghost flow.

    But improper piping with multiple circulators can be another reason for checks not holding. Incorrect primary secondary for example, and in some cases you need checks on supply and return piping, you can get circulation up and down a single return for example.

    I like hydronic checks best as they are considered 100% "bubble free" protection.
    If you have a basic brass swing with no teflon seat I doubt it is sealing tight enough even if installed properly too be doing much good.

    Caleffi has a nice union hydronic specific check with a choice of connections, press, 2 pex, sweat or thread. Very easy to retrofit and service if needed.

    thanks Bob, i do believe our repipe is quite good as far as proper pri/sec pipe design goes
  • tim smith
    tim smith Member Posts: 2,498
    Finding a reliable spring check is a bit daunting. I find most after a while tend to hang up and not do their intended job. IFC on circulatory after a # of years do the same too, the plastic shat gets a bit of a groove in it and won’t open. Does it’s job until then although. I like flo checks best, but after quite a few years they get pretty tight to turn from closed to open for service. Wish someone would make a high quality spring check with manual open lever. Would pay dbl or triple for that.
  • hot_rod
    hot_rod Member Posts: 18,203
    There are cases, especially like yours with large diameter piping where you can get reverse flow. It the piping goes vertical from the P/S main I would highly recommend a spring check on both the supply and return. The IFC should cover the supply side fine, add a spring check on the return for 100% flow stop.

    I prefer the check 8-12" away from the circulator, but the IFCs, while not a bets piping practice, do seem to work even in those turbulent conditions at the circulator discharge :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream