Grundfos & Myers - Different PUMP Series

Users who are viewing this thread

Bubba

New Member
Messages
22
Reaction score
0
Points
1
Location
Michigan
Does anyone have a handle on the different submersible pump lines for both Grundfos and Myers? In other words, what is their best line, next best, etc. within each company, and also if any of these lines are "floating stack" pump types as recommended by Cary Austin (as opposed to "floating stage with thrust pads" type pumps) for longer life?

I've looked at both companies websites and downloaded some of their recent documentation/data booklets, and I'm still not a whole lot wiser. Grundfos information for North America is the hardest to find, but both companies are completely unclear about which are their top lines vs. entry level. If you buy an iPhone, it's pretty clear which model is the top model, and which model has less features and/or lower quality. They tell you right up front so you can make a decision based on your budget.

Generally, I'm looking at 3" or 4" submersible pumps for well water, 5 gpm - 30 gpm, 1/2 hp - 3 hp range, residential and some irrigation. I agree with the CSV concept as opposed to questionable VFD's, so not particularly interested in variable speed pumps or control boxes (I don't think). Current case is a shallow well application, but there will probably be other applications later. My philosophy is putting the water system and septic systems in for a new build are "one time" deals, that I don't want to have to worry about for at least 20 years. So I'm not concerned about $500 here or there. More important in my mind is to get the very best quality and design for these systems at the start. I'll trim the budget on light fixtures and floor tile when the wife gets involved, lol.

For example, it's still not clear what the difference between the Grundfos "SP" line and their "SQ" line (other than the obvious 4" vs. 3" diameter). Assuming you have at least a 5" casing, is there any reason you would go to an SQ pump instead of an SP pump? And which line would work better with a CSV1A valve?

In Myers case, I THINK the Predator Plus line is their top line, but who knows? Or is the Rustler line better? Again, which model is better suited to work with a CSV1A valve?

Below are links to the most recent data for North America from both of their websites:
Grundfos "SP": https://api.grundfos.com/literature/Grundfosliterature-5605835.pdf
Grundfos "SQ": https://api.grundfos.com/literature/Grundfosliterature-5935105.pdf
Myers "Predator Plus": https://www.pentair.com/content/dam/extranet/nam/myers/data-sheets/m9108ws-predator-series-ds.pdf
Myers "Rustler": https://www.pentair.com/content/dam/extranet/nam/myers/data-sheets/m9109ws-rustler-series-ds.pdf
 

Valveman

Cary Austin
Staff member
Messages
14,599
Reaction score
1,296
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
Pentair, Meyers, Sta-Rite, Simmer, Flotec, are all made by Pentair. Probably more I don't know about. You have to look at the details in the sell sheets. It may say all Stainless Steel, but it is just a SS shell over a plastic pump. Not that a plastic pump can't be good, it is just deceptive.

However, even in plastic pumps you have the difference of "floating stage" or impeller, or "Floating Stack". Floating stack means the thrust is carried by the thrust bearing in the motor. Floating stage means each impeller drags a thrust pad of it's own, and the motor thrust bearing sees basically no weight.

Since a Kingbury thrust bearing in the motor has a film of water between the pad and plate surfaces, even with full down thrust from a deadheaded pump, it is basically frictionless. The floating stack can only float so much as it is held up by the motor thrust bearing. This keeps all the impellers just a few thousandths of an inch above the diffuser, and makes them basically frictionless as well, even with lots of downthrust.

The floating stage pumps are basically using very slippery plastic impellers (Acetal or Delrin) which is supposedly self lubricating. The more downthrust the more each impeller pushes against its thrust pad, as there is no film of water between the two. Even very slippery plastic has more restriction as more back pressure is applied. Because of this it would be impossible to make a floating stage type pump with Stainless Steel impellers.

Both use centrifugal type impellers, which magically use less energy as they are restricted with a valve or a deeper well and draw less energy. However, the floating stage pump causes more friction as the back pressure increases from the reduced flow, which almost negates the drop in power needed for the impellers. With the floating stack pump, like the Grundfos, even restricted to 1 GPM there is absolutely no friction on the thrust bearing in the motor or the impellers. This lets the power required decrease as it naturally does with a centrifugal impeller, because it is not inducing more friction in the process.
 

Valveman

Cary Austin
Staff member
Messages
14,599
Reaction score
1,296
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
Either will work fine with a CSV. You will just get a much better amp drop and less wear with the floating stack type pump like the Grundfos than with a floating stage like the Pentair. Some designs are made more for marketing and construction cost. Longevity of more than the planned 84 months is detrimental to a fluid company. Fluid meaning cash flow and has nothing to do with water or pumps. Lol.
 

Valveman

Cary Austin
Staff member
Messages
14,599
Reaction score
1,296
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
Not much difference in pumps within the Pentair company. Even with multiple names and/or models they are basically the same floating stage type pumps.
 

Valveman

Cary Austin
Staff member
Messages
14,599
Reaction score
1,296
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
The difference between the Grundfos SQ and SP is much more than just 3' or 4" in diameter respectively. The SQ has very and small few composite impellers that spin 10,700 RPM to do the same job as the SP pump does with more Stainless Steel impellers spinning at only 3,450 RPM.

The SQ also has some electronics in the motor, and has a 5 second soft start ramp up time. It can be used with the CU301 controller which makes it becomes an SQE and has variable speed control. It has an oil filled motor with ball bearings, not a Kingsbury. But it is a floating stack design. This makes the amps or power needed decrease about the same when spinning 10,700 RPM and restricted with a valve like the CSV as it does when the RPM is reduced with the CU301 box. That is what I mean when I say a VFD or variable speed like the CU301 is just trying to trick a pump into doing something it already does naturally. The CSV doesn't vary the pumps speed, it lets it do it's thing naturally. Lol!

The SP is also floating stack, has all Stainless Steel impellers, and diffusers. There are many copies of the Grundfos pump on the market today. You can tell the pumps with Stainless Steel impellers as they are held together with straps down the side. Plastic impeller pumps have smooth sides, no straps from top to bottom. Started selling the SP in 1973. They were made with a little thicker Stainless back then but the design has not changed much. Always been my favorite pump, just not favorite company to deal with.

Good information on their product catalog here. https://product-selection-classic.grundfos.com/catalogue.html
Just scroll down in the sub families to SQ and SP.

You will see they have lots of different pumps, but they are made for lots of different reasons. Like the SQ is for 3" wells, the SP for 4" and larger, and hot water circulators circulate hot water. :)
 
Last edited:

Bubba

New Member
Messages
22
Reaction score
0
Points
1
Location
Michigan
The difference between the Grundfos SQ and SP is much more than just 3' or 4" in diameter respectively. The SQ has very and small few composite impellers that spin 10,700 RPM to do the same job as the SP pump does with more Stainless Steel impellers spinning at only 3,450 RPM.

The SQ also has some electronics in the motor, and has a 5 second soft start ramp up time. It can be used with the CU301 controller which makes it becomes an SQE and has variable speed control. It has an oil filled motor with ball bearings, not a Kingsbury. But it is a floating stack design. This makes the amps or power needed decrease about the same when spinning 10,700 RPM and restricted with a valve like the CSV as it does when the RPM is reduced with the CU301 box. That is what I mean when I say a VFD or variable speed like the CU301 is just trying to trick a pump into doing something it already does naturally. The CSV doesn't vary the pumps speed, it lets it do it's thing naturally. Lol!

The SP is also floating stack, has all Stainless Steel impellers, and diffusers. There are many copies of the Grundfos pump on the market today. You can tell the pumps with Stainless Steel impellers as they are held together with straps down the side. Plastic impeller pumps have smooth sides, no straps from top to bottom. Started selling the SP in 1973. They were made with a little thicker Stainless back then but the design has not changed much. Always been my favorite pump, just not favorite company to deal with.

Good information on their product catalog here. https://product-selection-classic.grundfos.com/catalogue.html
Just scroll down in the sub families to SQ and SP.

You will see they have lots of different pumps, but they are made for lots of different reasons. Like the SQ is for 3" wells, the SP for 4" and larger, and hot water circulators circulate hot water. :)

Awesome explanation, thank you!!!

After reviewing the conditions for my current build, either the Grundfos "15SQ07-180" (3/4 hp.) or the Grundfos "16SP10-10" (1 hp.) meet the requirements. It seems the SQ series has the advantage of a little less hp. for the same performance, as well as integrated dry run protection. Or would you say the "SP" series is still the preferred model for this application?
 

Valveman

Cary Austin
Staff member
Messages
14,599
Reaction score
1,296
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
Horse power per gallon is pretty much the same in all pumps. Some maybe slightly more efficient than others. Usually the larger diameter pumps are the most efficient because larger motors are more efficient. Permanent magnets make a little difference. I still like the SP over the SQ as the SP is a dumb motor where the SQ has electronics inside.
15SQ07-180 curve jpeg.jpg


16S10-10 curve jpeg.jpg
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks