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Issue with grundfos alpha2 pump

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ThatF_inGuyInNY
ThatF_inGuyInNY Member Posts: 64
in THE MAIN WALL

hi all

I have a primary/secondary system with an indirect that I just installed. The heating circuit has been on for a while and I’m swapping over to the indirect from an electric tank. The indirect is a WM aqua plus, all of this is sent through a taco relay.

Anyway, everything is operating as it should except the alpha2 pump. The indirect is kicking on, triggering priority at the switch and sending power to the pump. The pump, however does not seem to being moving any water. It starts in auto adapt mode and bounces between 0-1gpm/7-10w. I put it in constant speed mode at the highest setting (III) and nothing changes.

I tried tech support who suggested maybe I had the ifc in backword. That’s not it, but i pulled it anyway just to check. Still didn’t work. I swapped it for a single speed taco 1/25hp dumb pump that I had lying around. This worked as it should. So I figured maybe the pump was bad. Before I ordered a new one, I figured let me check by swapping my heating circuit pump (the same alpha2 model) just to be sure. Well, sure enough this one exhibited the same behavior.

Any idea why this pump is refusing to go max speed? The input is a simple on/off from the switch, no variable voltage or anything like that. Tech support for grundfos is pretty terrible in general (they forwarded me to a field tech for a third party distributor).

Hoping you guys have some insight.

Comments

  • ThatF_inGuyInNY
    ThatF_inGuyInNY Member Posts: 64

    figured it out. Pump needs to be power cycled after changing modes. Once it kicked back on, it was sending 8gpm

    GGrossbjohnhy
  • GGross
    GGross Member Posts: 1,708

    Local manufacturer reps are typically responsible for all Grundfos tech support, warranty, and on large jobs they are usually the field techs to make repairs. Whether you like their pumps or not if you are in the field you will do well to get acquainted with Grundfos, Taco, and B&G manufacturers reps so you know who to call when something goes wrong in the future. Taco has really good factory tech support, but still nice to know the local rep (not plumbing distributor but the actual manufacturer rep!)

  • Sukhoi29SU
    Sukhoi29SU Member Posts: 169
    https://forum.heatinghelp.com/discussion/comment/1872342#Comment_1872342

    glad I read this. My heating plan calls for auto adapt mode. I’ve never been able to figure out if auto adapt is working properly, so I resort to the III setting. You’re saying that once you change modes, you unplug the pump and plug it back in, in order for that setting to lock in?

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