The Dreaded Grundfos CU301

Discussion in 'Pumps and Tanks Well Forum & Blog' started by twobeemers, Dec 26, 2008.

  1. twobeemers

    twobeemers New Member

    Richfield, WI
    The well guy was out again this morning replacing the CU301 Controller for the 3rd time in 18 months. The house was built new in '07 and we needed a high capacity pump (4 full baths including one shower with 6 shower heads - one of the wife's very few "must haves" when we built) and that's what we ended up with.

    So we're on controller #3 or 4 and so far, no one has been able to tell me why they keep failing other than a shrug and "electrical". So have a new controller but it's just a matter of time before it fails from everything I've been reading. So I want to take some action - besides stashing a few gallons of drinking water in the basement - to cover myself for next time I wake up and HAVE to get to work and find I can't take a shower.

    To that end, I'm likely to take the numerous suggestions here and install a Cycle Stop valve and a pressure switch (which looks like should cost about the same as a new controller anyway). Can I install the CSV and run with the controller until it pukes and then buypass it with a pressure switch, or should I jsut trash the controller box at my first opportunity and go from there?

    I've also been reading that I can (temporarily) bypass the controller and the pump will run (provided it's not trashed). How would I go about hooking one of those up so I can switch over to it in the event of another failure?

    Thanks in advance.

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    Last edited: Dec 26, 2008
  2. valveman

    valveman Moderator Staff Member

    Lubbock, Texas
    The number of times I have replaced the CU301 controller is staggering. Even on this forum the list is getting long. See this list from a search for CU301.

    The controller is trying to accomplish the same thing as the CSV. If you use both at the same time, they will be fighting each other. If your tank is still good, all you need is a CSV and a pressure switch. You should return the CU301 for a refund if possible. If it was a warranty replacement, maybe you can sell it on the Internet and pass the problem to someone else.

    Use a little less air in the tank to make up for the soft start feature, ie. 40/60 switch, use 30 PSI air in the tank. Otherwise you will see a drop in pressure before the pump gets up and running.
  3. twobeemers

    twobeemers New Member

    Richfield, WI
    Not a bad idea (selling it on ****).

    So what sort of timeframe are we looking at to install the CSV? Is that a "send the wife to the in-laws for the weekend" sort of thing, or a Saturday morning sort of thing?
  4. Gary Slusser

    Gary Slusser That's all folks!

    How long it takes depends on how speedy you do plumbing. :) But usually not more than a couple hours at most and a couple of buckets of water in the house for flushing etc. and you're done. That's unless you want she who you love and admire and must obey to 'get away' for a couple days...
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