Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Check Valve Noise

I have installed a Munchkin as per the O & M manual on a job. I put the boiler circ pump on the return side as stated in the installation guide. I installed a Grundfos UP 26-64 and have a noisy check valve. Does anyone have any advice on how to correct the noise problem. I installed a Danfoss Pressure Diff. Reg as per the installation manual and it too made noise at first but currently no longer makes any noise.

Right now I am running temp heat to 2 hot water coils. I have 4 more zone valves to supply to when I get the baseboard installed.

I appreciate your help in this matter.



Did I do something wrong? Please let me know because I have a feeling the owner will not want to deal with the noise and I don't think he should have to.


  • Jerry Boulanger_2
    Jerry Boulanger_2 Member Posts: 111
    The check valve is likely

    too big. Line size check valves often chatter because the fluid velocity is not high enough to keep the valve fully open.
  • bob young
    bob young Member Posts: 2,177

    wow about a flow control [b & g or taco ] in lieu of a conventional check. they are pretty much silent.
  • John Siegenthaler
    John Siegenthaler Member Posts: 14

    I would also recommend at least 12 pipe diameters of straight pipe upstream of the check valve to reduce inlet turbulence. I've found this works well with spring-loaded checks.

  • Justin Gavin
    Justin Gavin Member Posts: 129
    For further Refrence

    Thanks for the info but I guess my next question is this. If I can't offer 12 pipe diameters of betweent the discharge of the pump and the check valve what should I do? Install a flow control valve?

    I have attended a radiant class a last week and they were talking about a heat trap. I liked the idea but kinda fuzzy on the exact requirements and design. Any rules of thumb or advice would greatly be appreciated.

    Thanks Siggy

    PS. I have the first addition of your book and have ordered the second edition just yesterday. What a coincedence.

  • hr
    hr Member Posts: 6,106

    the check would be sized and installed in such a way it doesn't have a chance to make noise.

    If only we lived in a perfect hydronic world :)

    A couple other thoughts. Can you fit a Grundfos 15-58 on, speed 3, into the 26-64's place. Check the curve on the 15-58, it gets close to the 26-64. The 15-58 would give you a pump with a "quiet" intergral check.

    Hey Grundfos, when will we see the 3 speed, intergral check 26 series circs.????

    Or replace the check with one of the various soft seat, low pop pressure models. This would soften the noise, and the low pop spring may make the issue disappear altogether.

    Conbraco, for one, offers soft seat checks with various spring choices.

    hot rod

    To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
  • Justin Gavin
    Justin Gavin Member Posts: 129
    Thanks for the info

    Well I have a 26-64 in place with a soldered check valve in. I will probably remove it and place a 58 in. I should be OK. I am just kicking myself because I already placed the same check valves in 3 other spots that I havn't started up yet and now I will probably replace them.

    The problem is that I used Pro-Press fittings and they are quite expensive to be throwing out. Oh well. A valuable lesson learned here.

    Thanks to everyone for their help.


This discussion has been closed.