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Alpha motor fits non-alpha 15-55 body?

BigRob Member Posts: 318
Does anyone know if an Alpha motor will fit a stainless 15-55 body? I have a stainless body that is fine and if a alpha motor fits, I'll just buy the whole cast iron pump and swap the motor. The 15-55 series bodies look the same to me.


  • BigRob
    BigRob Member Posts: 318

  • heatpro02920
    heatpro02920 Member Posts: 991
    looks like it will go to me..

    give it a try, or call g-fos to be sure..
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,225

    Frame size will likely fit. You'll have to check on the impellor though.

    I believe I would contact Grundfos

  • hot_rod
    hot_rod Member Posts: 19,279
    I know

    the Alpha head fits a 15-58 and 15-42 body. But the performance will probably not be the same as the stock Alpha in the correct volute.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • BigRob
    BigRob Member Posts: 318

    I think I'll give it a shot out of curiosity and will report back.
  • BigRob
    BigRob Member Posts: 318
    Just to follow up, I did swap the Alpha motor into a stainless volute. It works great, and upon inspection, the old motor used the same stainless seal plate, impeller, and other parts as the Alpha.
  • icesailor
    icesailor Member Posts: 7,265
    Why did it have a Stainless pump in the first place? Was it Potable Hot Water?

    In my lifetime, I've seen a lot of dead CI Series 100 B&G pumps on the floors of boiler rooms with a red, dead pump stuck inside a gold painted pump housing with a very old gold painted bearing and motor assembly on the floor, where someone replaced the first bronze pump with a Cast Iron pump assembly in to the bronze pump head and all the ones who came later did the same because once they found out how much more the bronze pump was, they just bought another improper Cast Iron one.

    Taco makes a Bronze Bearing Assembly for their 110 pumps. I've seen more than my share of green leaking bearing assemblies with bronze colored motors and pump heads.
  • BigRob
    BigRob Member Posts: 318
    The stainless volute was used in a dhw recirculation system. The alpha motor was brand new. The motor I removed has the exact same wetted parts as the alpha and the pump impeller was the exact same part since is was also a 15-55 class pump. It's working great. For a German company I'm pretty surprised how wasteful Grundfos is. No spare parts that I know of, and no sales of motors, only. Pretty poor. This is a good opening for Taco to exploit.
  • Gordy
    Gordy Member Posts: 9,537
    In this day we live in a throw away society. Not condoning it. But when one looks at labor to replace a part of a component verses the whole component it's sometimes cheaper to just replace the whole thing. Then there is the inventory of parts for whole components. Look at all the circs today much more to choose from than long ago.