[RE-wrenches] Grundfos

Mon Nov 8 17:28:24 PST 2010

I believe the F3 error code was the known communication issue with the CU200
controller.  Basically, it loses communication with the pump and so throws
the error code.  I saw a bunch of CU200 controller issues in my previous
job; GF acknowledged they had a bad batch, and were pretty good about
swapping them out.
The good news is, the CU200 controller is not required for the pump to run.

The important thing to remember with the CU200 is that it doesn't actually
"do" anything to the power going to the pump.  If the float switch signal
circuit closes, the controller doesn't interrupt power like a traditional
switch.  Instead, it sends an electronic "stop" signal to the pump, which
turns itself off.  The conductors down the hole are always energized
whenever the sun is shining (assuming it's a PV array powering the pump).
 Similarly, the controller doesn't actually "measure" the wattage flowing
for its display -- it just reports what the pump tells it that it is
drawing.  I believe the F3 error comes up whenever the controller loses
communication with the pump.  Take the controller out of the circuit, and if
there's enough PV power to overcome the lift the pump should run.

In fact, I believe one of the greatest saving graces of the SQ-Flex pump is
the ease of troubleshooting.  Go out into the field with a small 1,000 watt
or larger generator or inverter.  Connect 120V AC directly up to the wires
going down the hole, and if you get water, the problem isn't with the pump,
so you can focus your attention to the array.  Add a CU200 into the circuit,
and measure the gallons per minute produced (still running from 120v
source).  Compare the gallons per minute and the wattage consumed by the
pump as shown on the CU200's display, against the flow and energy charts for
the designed lift in the SQ-Flex service manual.  If the flow is lower or
wattage is higher, either the water table has dropped (increasing lift), or
the pump is beginning to bind (increased friction).

BTW, for those of you using the Flex in a pressurizing system, it's
important to remember that the CU200 doesn't directly control the pump -- if
there's a loss of communication, the pump will continue to run, causing a
potentially damaging over-pressure event.  I use a SQ-Flex running off 120v
inverter power at my home in New Mexico.  I have a CU200 in the circuit so
that I can keep track of the water level/pump friction/energy consumption,
but I use a standard pressure switch to control when the pump runs.

Phil Undercuffler

On Mon, Nov 8, 2010 at 4:47 PM, Gary Gordon at SYV Solar
<gary at syvsolar.com>wrote:

>  Wrenches,
>
> More details on the Grundfos failures:
>   1st failure 11 SQF-2 w/ 204ft TDH
>   2nd failure 6 SQF-2 w/ 220ft. TDH
>   3rd failure  6 SQF-2 w/ 253ft. TDH
>
> All controllers were displaying F3 failures, there was voltage at the well
> head. Only one replaced so far and seems to work fine.
>
> Any ideas or similar problems?
>
>  Gary Gordon
> Santa Ynez Valley Solar
> P. O. Box 688
> Santa Ynez, CA  93460
> 805 688-1213
> Gary at SYVSolar.com
>
>
>  ------------------------------
> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Mike Nelson
> *Sent:* Saturday, November 06, 2010 10:07 AM
>
> *To:* RE-wrenches
> *Subject:* Re: [RE-wrenches] Grundfos
>
>  Doug,
> Thanks for the feedback. I have to install the monoflo, because it was
> purchased 2 summers ago, but the customer didn't have the site work done to
> install the pump. This summer the site work was finished and now the
> customer is ready to have the system installed, so wish me luck!
>
> DC Power is getting out of the pumping biz, so is Wholesale solar up north,
> hopefully Solar Depot will remain in it. Our only other option is to go
> through the plumbing supply houses.
>
> I hear the bugs are being worked out of the Lorentz pump line, anyone have
> any experience with them?
>
> Mike Nelson
> MD Electric & Solar
> Gualala, Ca.
>
> On Sat, Nov 6, 2010 at 7:45 AM, Doug Pratt <dmpratt at sbcglobal.net> wrote:
>
>>  Mike, from another Mendo native, don’t do the Monoflo.  DC Power is
>> getting out of the pumping biz, and we’re the only Monoflo distributor in
>> the US.  Our experience with Monoflo hasn’t been good. We’ve seen a number
>> of pump failures recently, support from the manufacturer is pretty thin, and
>> troubleshooting in the field is poorly developed and documented.  Basically
>> it’s… pump not working?  Try plugging in a new controller. Still not
>> working? Plug in a new pump.  Dealers don’t keep expensive pumps on the
>> shelf in case of breakdowns, so repairs usually end up taking weeks. Not
>> good for dealer/customer relations!
>>
>>
>>
>> DC Power is getting out of water pumping because we just don’t have the
>> technical bandwidth anymore. We’re being pressed so hard by the
>> rapidly-expanding grid-tie market that our tech support crew is getting
>> loved to death. There’s no time. I’m sorry to see it go, I found water
>> pumping projects challenging and interesting, but the tech cloning project
>> has hit some snags.
>>
>>
>>
>> From a sales perspective, the Grundfos SQ Flex was the best of the lot. We
>> heard the fewest problems from them, and those problems were usually on the
>> surface (the CU200 control).
>>
>>
>>
>> Doug Pratt
>>
>> DC Power Systems
>>
>>
>>
>> *From:* re-wrenches-bounces at lists.re-wrenches.org [mailto:
>> re-wrenches-bounces at lists.re-wrenches.org] *On Behalf Of *Mike Nelson
>> *Sent:* Friday, November 05, 2010 5:37 PM
>> *To:* RE-wrenches
>> *Subject:* Re: [RE-wrenches] Grundfos
>>
>>
>>
>> I have also installed several Grundfos SQ Flex submersible well pumps, and
>> had trouble with them, primarily with the control systems, the low water
>> shut off sensor has failed on several pumps, and the CU200 control boxes
>> have failed. The pumps themselves have held up so far, and seem to be very
>> efficient. I wish there were more solar direct well pump options, I've tried
>> the ETA pumps, the Sunpumps (which are great for low head, low flow) and am
>> about to try a Monoflow. Any other thoughts?
>>
>>
>>
>> Mike Nelson
>>
>> MD Electric & Solar
>>
>> Gualala Ca.
>>
>> On Fri, Nov 5, 2010 at 4:40 PM, Gary Gordon at SYV Solar <
>> gary at syvsolar.com> wrote:
>>
>> Wrenches,
>>
>>
>>
>> I set up the PV arrays for six Grundfos SQ Flex submersible well pumps on
>> a cattle ranch. The first three have failed (in exact order of installation)
>> in about a year. Anyone else experiencing similar problems? I had always
>> heard great things about their equipment, is it time to look elsewhere?
>> Where?
>>
>>
>>
>> Gary Gordon
>>
>> Santa Ynez Valley Solar
>>
>> P. O. Box 688
>>
>> Santa Ynez, CA  93460
>>
>> 805 688-1213
>>
>> Gary at SYVSolar.com
>>
>>
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