Grundfos SQF pumps

[Tankgirl74]

Hi folks,

I’m supporting a permaculture farm to replace a groundwater pump that can run on both solar and the grid. We’ve narrowed our selection down to one of two Grundfos pumps – the 22-SQF-220 or the 30-SQF-160. In looking up the pump specs and parameters, the website cites for both models: “The 3″ SQFlex pump with helical rotor is for high heads and low flow rates.” Other sources call both of these pumps centrifugal pumps. I’m am not a pump expert, so I’m wondering if someone with more experience with these systems could answer a couple of quick questions:

(1) The difference in the literature (helical/high head/low flow vs centrifugal/medium head and flow) – Can someone in the know please confirm which kind of pump these are?

(2) I’m being asked what the practical difference is between centrifugal and helical pumps beyond the basic capacity differences cited by most of the literature. Any thoughts on this from folks who have field experience with both types of pumps?

Thanks!

[Bala]

Looking at info online there are both Helical and Centrifugal in the SQF range.

Helical is positive displacement so will generally supply from a greater depth ( Higher Head ) than a centrifugal pump can.

If it were me I would find a local supplier/installer, they will will know the area and best advise on the pump to use.

Some things to consider are head, supply rate needed, what the bore is capable of sustaining, as well as water quality.

[Tankgirl74]

Hi Bala,

Thanks for taking the time to respond. Yes, I checked the grundfos website and it is claiming that the pumps are helical in one part of their website and centrifugal in another. I was just hoping that maybe someone with some hands-on experience with these systems could verify which they are.

Also, the two pumps I cited in my original email are sized based on all the basic design factors you suggested. I’m just trying to get a feel for the differences in practical use terms, like maintenance needs and other end-user relevant considerations that may come up during the life of the product.

Looking at info online there are both Helical and Centrifugal in the SQF range.

Helical is positive displacement so will generally supply from a greater depth ( Higher Head ) than a centrifugal pump can.

If it were me I would find a local supplier/installer, they will will know the area and best advise on the pump to use.

Some things to consider are head, supply rate needed, what the bore is capable of sustaining, as well as water quality.

[Bala]

Sorry I cant help with the difference, as you have found their website and info is not great.

I help on a some cattle properties in Australia that have bores. Generally the pump will only need to be pulled if it fails. One property has had pumps in for over 15 years without issue. They and their supplier are finding that now that same brand pumps are not as good as they once were so life expectancy is unknown/shorter.

I can only suggest to talk to grundfos and local supplier to determine what is best for your site. A local supplier that will handle warranty claims or problems is important.

[Tankgirl74]

Hey Bala - no problem. Good to be aware about the potentially shorter life expectancy. Thanks for offering your experience and perspective.