Noisy 007-F5 circulator

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geze
geze Posts: 2
in THE MAIN WALL

Hi,

I wonder if anyone can identify what is wrong with this circulator from the audio:

https://share.descript.com/view/lx18fzVqJyV

There is also a diagram and more information in the video.

Background. The system is about 20 years old. It has 4 007-F5 circulators.
3 have never had an issue and are quiet. One has been replaced 3 times. The one in the video was replaced in 2023 and was quiet until this fall. This circulator has a long loop compared to the others. It still produces heat.

Reading other posts it seems options are a failing circulator or air in the system that is causing cavitation? Do those sound different?
I guess I'm wondering what is wrong at this point and why does that circulator have trouble?

Thanks for your help!

Comments

  • leonz
    leonz Posts: 1,980

    You have a failing circulator/cartridge, you need to change it. The two TACO's I had made noise and the B+G NRF 25 I just changed out was worn out made no noise and I did not catch it sooner.

    geze
  • geze
    geze Posts: 2

    Thanks Leonz.

  • mattmia2
    mattmia2 Posts: 18,298

    what kind of system is it? is it a gravity conversion? is it all copper? is it an older black iron pumped system? is it part pex or some other plastic tubing? is that tubing oxygen barrier? is the pressure high enough to keep it from cavitating?

  • hot_rod
    hot_rod Posts: 28,613
    edited 1:36AM

    That is unusual to replace 3 circs in the time periuon. Could be that zone never gets air free? Is there a central air purger?

    You need at least 5 psi at the circulator inlet. It is a temperature/ pressure relationship to prevent cavitation. If for some reason the boiler runs hot, maybe 203°, you need about 7 psi at the pump suction.

    Dirty fluid takes out bearings also.

    Is the motor mounted vertically by chance?

    Grundfos inlet pressure.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream

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