Grundfos cu301 Pressure Problems

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by, Jun 28, 2008.

  1. New Member

    Jun 28, 2008
    Have a 5 year old Grundfos cu301 system with 2 gal pressure tank. Last winter the controler changed from 70psi to 40psi and we could not change the pressure. Well repair came and said system was fine, but system had been locked with a remote control. He put controler back to 70psi and made sure pressure in tank was 70% of system pressure. Acouple days ago, we filled 30,000 gal swimming pool with 3 garden hoses in 2-1/2 days (there is no problem with well supply). Shortly after that, the controler dropped to 40psi. We reset it back to 70psi. After one day the controler dropped back to 40psi and we now can not switch it up to 70psi. It is like in locked mode, but the locked indicator light is not constantly on. It does come on momentarily when controler is turned on and off. We did not get a remote controler with the system. Is there a way to increase the pressure without calling well repair every time? :confused:
  2. valveman

    valveman Cary Austin Staff Member

    Mar 15, 2006
    Pump Controls Technician
    Lubbock, Texas
    Unfortunately you have already exceeded the average life expectancy of that system. 4 years seems to be the average life. I know of a very few that have lasted 9 years but, many have died less than 2 years of age. Hence the 4 year average life, which I believe to be optimistic. Those variable speed pump systems are made to sell and for the pump company to make a lot of money on, not for the home owner to get many years of trouble free service.

    Now here is the rub. The new CU301 controllers will not work with pumps that are more than a couple of years old. Most likely you will have to replace the pump, motor, and controller to get it back to working again. Even the remote control that the pump installer has will have to be updated or replaced to work with the newer pumps. And no there is nothing you can do to repair it yourself. There is nothing that the pump installer can repair himself. If flashing a new program with the remote does not work, then replacement of the equipment is the only way to fix your water problem.

    Purchasing something that is expensive, short lived, and non-repairable helps the manufacturer with their "fluid system". "Fluid systems" have nothing to do with water but, are a manufacturers ultimate goal. It just means that cash is flowing fluidly to the manufacturer.

    All the stuff that goes along with the variable speed part of that type system, is what gives the most trouble. You can run those type pumps without the CU301 controller. If you just plug them straight into the power supply, they will work at a constant speed. The you could cut the power supply with a regular 60/80 pressure switch, and use a Cycle Stop Valve to maintain the 70 PSI constant. This will actually work better than using the CU301 controller. Then when the little 10,600 RPM pump also lays down, you can easily replace it with a standard long lasting 3450 RPM pump.

    A good pump system should last 15-20 years without problems or added expense. When you opt for the computerized variable speed type systems, they are as expensive to replace and don't last any longer than any other computer. Problem is, when this computer "blinks", you are out of water.
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