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Rattling Alpha

I've had an Alpha in use for the system pump for a few years and while it works just fine, it has always made a rattling noise when running at anything above the slowest speed. Being a early adopter this was installed very soon after the Alpha became available. I seem to recall hearing on the Wall that many of them had a bit of a rattle. Have you seen (heard) this and are they any quieter now?

Larry

Comments

  • hot_rod
    hot_rod Member Posts: 15,022
    Could be something such in the check or the check loose in the volute?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Larry (from OSHA)
    Larry (from OSHA) Member Posts: 691
    Thanks for the idea. I don't think the check itself is loose but I am trying to avoid taking the pump out of the system since it works and it's pretty cold outside at the moment. Just an annoying little noise.
  • ced48
    ced48 Member Posts: 468
    I have a 15-58 that is making the same sounds. Just replaced the IFC valve, still makes the rattle. Also, now when it shuts down, it makes a little squeaking sound. Drives me crazy-
  • hot_rod
    hot_rod Member Posts: 15,022
    could it be something lodged in the impeller? I've seen solder balls, copper shavings, teflon tape stuck inside the small vanes of circulators.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Larry (from OSHA)
    Larry (from OSHA) Member Posts: 691
    So my curiosity got the better of me and I pulled the pump out and separated the motor from the volute. The check seems fine and there was nothing found in the impeller. There is however about 1/8 to 1/4 inch of end play on the impeller shaft. Is that normal? At least it moves water like it should. It's about 9 below here today.
  • hot_rod
    hot_rod Member Posts: 15,022
    that is a new one on me, I have never had a rattle noise like that. Did you contact Grundfos or the local rep?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Larry (from OSHA)
    Larry (from OSHA) Member Posts: 691
    No I have not. I may look into that but at least it works like it's supposed to. :)
  • Larry (from OSHA)
    Larry (from OSHA) Member Posts: 691
    Success!

    I have too much time on my hands. I pulled the check out and no more rattle. Have not replaced it and I'm trying to figure out why I actually need a check there at all. With zone valves up stream of the circ I don't really think it makes much difference.

    Larry
  • hot_rod
    hot_rod Member Posts: 15,022
    True that, not every application requires that check. Unless you have signs of un-wanted flow you should be fine without it.

    Usually if the check is bouncing or making noise the flow is too low to fully open, and keep it open. Or something is physically interfering with the movement?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • icesailor
    icesailor Member Posts: 7,265
    I always considered Zone Valves as motorized flow checks. Who needs IFC's on circulators with Zone valves. One full sized flow check on the supply will cover the whole system and cost less.

    Back to basics.