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.

grundfos circulation pump leaking

Options
beezer
beezer Member Posts: 21
its starting to drip from the parting line where the pump joins the motor. pump is only about 5 years old... I really don't want to buy a new one.

I'm guess a shaft seal

I haven't done anything to it yet.

Comments

  • Big Ed_4
    Big Ed_4 Member Posts: 2,819
    Options
    There is a O ring .

    There was an error rendering this rich post.

  • beezer
    beezer Member Posts: 21
    Options
    thanks... how hard to replace? and I just went & checked it a bit ago & its not leaking when its circulation hot water.. it only leaks when its cold. we had a pretty long stretch of warm weather & the boiler (Lochinvar Knight mod/con) spent a lot of time off and only firing low. thats when the pump started weeping. btw this is the main boiler circ pump, the 2 zones have another pump, the sidearm has another as well
  • mattmia2
    mattmia2 Member Posts: 9,850
    Options
    Is it a wet rotor pump? a picture would help. if it is a wet rotor, are the screws that hold it together tight?
  • Steve Thompson (Taco)
    Steve Thompson (Taco) Member Posts: 204
    Options
    If the pumped fluid is cold and the ambient temperature is warm/hot with high humidity it likely condensation building in the stator area. There are condensate drain holes in the stator housing to release the water. So, it's not bad unless you plug the drain opening as the stator will flood.

    This is typical of all wet rotor circs.
  • HomerJSmith
    HomerJSmith Member Posts: 2,483
    Options
    Describe the leaking process, the amount of drip, the duration of the drip. Pics help.

    There ain't no shaft seal if it is a wet rotor pump.

    The four allen screws that hold the motor housing to the pump volute should be tight, as mattmia2 suggests. After tightening and it still drips, you may need a new gasket, not easy to find. I may be able to help you with that. What is the pump model #.

    The gasket is not an o-ring but a flat doughnut shaped gasket.
  • Steve Thompson (Taco)
    Steve Thompson (Taco) Member Posts: 204
    Options
    As it only "leaks" pumping cold water I doubt if it's a mechanical (gasket) issue. Still think it's condensation.
  • HomerJSmith
    HomerJSmith Member Posts: 2,483
    Options
    Could be, but the pipes are at ambient temps and should show condensation, too, I would think. It's not a glass of iced lemonade. Perhaps, the boiler is in a basement with a dryer that's venting into the environment with humid air. More information is needed with pics.
  • mattmia2
    mattmia2 Member Posts: 9,850
    Options
    It might be evaporating faster than it is leaking when it is hot.
  • HomerJSmith
    HomerJSmith Member Posts: 2,483
    Options
    As my Dad always said, "If the rate of evaporation exceeds the rate of drip, you don't have a leak."