Grundfos SQE10-5 and CU301

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rossy65

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I purchased one of the Grundfos constant pressure pumps off **** and installed it several months ago in my 60' well. The new 10SQE-5 1/2HP pump replaces an 2 year old 1HP Jet pump that was just not providing adequate pressure.

The new pump has been in-service for about 4-5 months and provides GREAT pressure. I recently added a 3/4" diameter faucet line and have been irrigating my yard pretty heavily this summer. At the same time I installed a filter in the line as we have an iron/sulfur bacteria problem. I discovered that I have been pumping a *lot* of sand. The filter fills up about a every week or so. (The home is a tear down remodel project.. so we don't live on site). Just lawn sprinklers so far.

Recently the CU301 is indicating "OVERLOAD" and runs the pump at a reduced speed. My guess is that the impeller chambers may have filled up (partially) with a fine sand. Alternately one of the two check valves in the line at the top of the down pipe, and as the line enters the house could be restricting the flow.

How difficult would it be to disassemble the pump and clear the pump body of sand? it appears that the motor/pump can be separated by unscrewing, but I don't have a service manual.

Also... I'm thinking a LAKOS SUB-K sand separator shroud would be a good investment. Since the pump has run fine for several months under varying load conditions, I believe that it is properly sized for the work, but there is a chance I have chosen poorly and should have purchased a 3/4HP pump.

The sustained flow rates from the well seem to be much higher than the 12GPM I had projected. (I have not measured this).

From all the reading I have done, it appears the OVERLOAD indication on the CU301 will only appear if the motor exceeds the 5.2A current, and this would only happen if there was excessive back pressure or resistance to movement of the impellers.

I pulled and inspected the body of the pump last week, no exterior obstructions. With the pump running, it seemed that the flow output may be reduced somewhat from when I did the initial installation. This is with the line pulled 10' or so so I can observe the free flow of water discharging.

Just curious as to possible things to investigate. I'm going to try and reach a Grundfos rep locally here in Portland to see if they can open the pump body and inspect it for obstructions. I'd like to do it myself it possible.
 

Valveman

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"Working great" and "only lasted a few months" don’t really go together. Sand is your first problem, then picking a pump that can’t handle sand is another problem. That pump spins 10,600 RPM instead of the normal 3450. You run some sand through at 10,600 RPM and the impellers won’t last long. When the impellers and the shaft wear, they knock the top bearing out of the motor and it starts pulling high amps, if it will even run. Not much you can repair with one of those, they plan it that way.

Sand can be washed out without disassembling the pump. And if it were sand locked, it wouldn’t turn at all.

Someone deleted some of the good parts of the following threads but, you can still get the picture. You are not the only one having problems with this type pump.

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ighlight=cu301

https://terrylove.com/forums/show...ght=mono+drive
 

Mr.Nice_Guy

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There's an online catalog program that will show you the exploded view.
www.webcaps.com Catalog>Groundwater>SQE model B & B>10SQE>
- do the "-160" - it's a 1/2 HP. You might not see the exact part number (SQE10-05-***) -the *** is just the # of impellers. From there you can see the pump curve - then look for the 'links' icon in the top right. You can find the service documentation and more.

However I imagine that there's some special tools required, and you'd definately void your warranty. Contacting the distributor that sold it is the best course of action.

Sand will destroy any pump you put down there. It's just a matter of time. Putting a pump that can "Handle" sand [interesting concept...] would just fix a symptom. You need to fix the problem.
 
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