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I replaced my circulator pump on home boiler. It is leaking on one side of the lower flange.

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I replaced a Grundfos circulator pump on my home boiler. It is vertical, pumping up. With check valve. I got the new gaskets and bolts. The old one came out OK and the new one went in harder and I had to lift the pipes a little bit. I nudged it over and got the bolts lined up and tightened the bottom ones to let the water rise up and maybe drive out the air. Then I opened the first valve, to the ballast tank I think and water (and air?) came out the top loose flange so I tightened them up.

The water (and air?) was hissing out the back side of the bottom flange so I tightened them up and it kept leaking out the back of the bottom flange. I took it out and looked at the gaskets to see if they looked OK. They did. There was enough leaking so I did not turn on any more water valves.
Any ideas? Should I have used faucet grease on the gaskets?
UPS15-58FC, 3-Speed Circulator Pump,
Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,454
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    A flange is a little more forgiving than a union -- but not much. I'd suggest taking it apart again, and getting the flange halves lined up as perfectly as you can -- left, right and especially flat and parallel to each other. Then slip the gasket in and -- making sure everything stays aligned torque it gently -- go in a star or criss-cross pattern. It would be best if the pipes could be held in the correct position in some other way.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • eclecticmn
    eclecticmn Member Posts: 121
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    Thanks I will try that. Also, how do I remove a check valve on the 58FC? I may have to fall back on the old one and see that the check valve is gunked up. I only have one pump and one zone.
    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.
  • hot_rod
    hot_rod Member Posts: 22,268
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    Flat gasket, or the o ring that fits in the groove? The flat ones can hang up if the gap it too tight to slide the pump into the opening

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • eclecticmn
    eclecticmn Member Posts: 121
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    Flat gaskets in a square groove.
    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.
  • eclecticmn
    eclecticmn Member Posts: 121
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    I mean the round gasket does not have a round cross section.
    https://www.supplyhouse.com/sh/control/product/~product_id=519610
    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.
  • hot_rod
    hot_rod Member Posts: 22,268
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    square cut o-ring, officially 😉

    Those should seal fine, even with some misalignment. Assuming it stays in the groove
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • eclecticmn
    eclecticmn Member Posts: 121
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    Thanks to all again. I took the advice. I propped up the pump piping with a 2x4 from the floor and aligned it at ease then lowered it. So far so good. I was getting frantic.
    Home owner near Minneapolis with cast iron radiators, one non working slant fin now ripped out, and hot water heat.