Grundfos SQ Flex F3 on CU 200

James WilsonJames Wilson Registered Users Posts: 28 ✭✭
edited August 2020 in Solar Water Pumping #1
I'm helping a neighbor out with this.  I've done electrical engineering for around 40 years, but I'm just now becoming familiar with this system.

I can't easily get to his pump so I don't know the exact model number.  It was purchased to run off of about 300 watts of solar or generator and is delivering water from a tank fed from a spring up about 200' in elevation to a tank to gravity feed their house.  It has a CU 200 and IO (I forgot the IO box number, but it's not a 50).  It has been in operation for around ten years.

So today he noticed that his reservoir near his house was low and found the CU 200 says F3.  I measured around 63 volts from the solar panels in partial sun near the pump.  The pump is in a tank and difficult to get to, but that's what I measured at the underwater cable about ten feet away from the pump.  The voltage stays the same whether the pump is connected or not and I measure no current flowing.  There is no current flowing with the generator connected to the CU 200 instead of the solar panels either.

I ran 110 VAC to the pump, directly at the pump, bypassing the CU 200 and measure around .4 amps of current.  I haven't been able to get to the tank to see if it's actually pumping.  But I'd expect the pump to be able to use more current than this.

Am I missing anything?



  • James WilsonJames Wilson Registered Users Posts: 28 ✭✭
    It looks as if no water was pumped overnight in spite of using 0.4 amps of 110 VAC all night.  And the pump model might be SQF - 3 according to some old paperwork with the manual.
  • James WilsonJames Wilson Registered Users Posts: 28 ✭✭
    Does Arizona Wind and Sun support these pumps at all?
  • BB.BB. Super Moderators, Administrators Posts: 33,319 admin
    I believe that NAWS does support those pumps (I do not work for NAWS--I am just a random volunteer here):

    Some of these pump may/do have a run-dry shutdown feature... Water levels in well OK? It may be a pump failure--But I have no idea on how to debug.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • James WilsonJames Wilson Registered Users Posts: 28 ✭✭
    Thanks Bill, I guess I'll just have to contact them directly...
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,627 ✭✭✭✭✭
    They will help with grundfos if you bought it from NAWS.

    They may give you general advice. Pumps have life expectancy and your reading sounds like it is at the end. It would be better if it did not draw any current as the wiring could be open.
    "we go where power lines don't" Sierra Nevada mountain area
    E-mail [email protected]

  • jonrjonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited August 2020 #7
    F3 = no contact to pump.   If power is getting to the pump, then it may be bad.

    I am available for custom hardware/firmware development

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