which plays nice with CSV - Goulds or Grundfos?

[stallhorn]

Hi all,

I got a CSV a few months ago and it has been working great boosting the water pressure in the house. Now the pump in the well gave up the ghost, probably because it is the pump that was sent down there about 23 years ago when the house was built.

I need to get the pump replaced and wanted to make sure to get something the plays nicer with the CSV.. I have two pumps offered to me by the well company:

- Goulds 7HS05422C 1/2 HP - ~2700 installed
- Grundfos 15SQE07-180 3/4HP - ~ 3200 installed

This is for residential application (with kids out of the house), so water use is minimal.

Reading up on this, goulds says it is a 10 stage pump and grundfos says it is variable. I have no intention of adding a VFD; CSV is giving me that. I am looking for efficiency and longevity.

Thanks.

 

[Reach4]

The Grundfos 15SQ07-180 3/4HP would be what you want in an SQ, rather than a Grundfos 15SQE07-180 3/4HP, but actually, they are both not the ideal pump if the Goulds 7HS05422C can do the job. That Goulds is a 1/2 HP 7 gpm pump. So a 5 or 10 gpm 1/2 HP SQ pump could be a better choice in the SQ world.

How far down do they intend to set the pump, or if you don't know that, how deep is the well, and how far down is the static level of the water?

The SQE takes signals from a controller via the power line to signal the variable speed. While an SQE can function as an SQ, it has a price premium that you do not need.

For either, you would probably want a flow inducer assuming a 5 inch or bigger well. Cheap. Search for information in the search box, above, and if you want more info on that, ask.

The SQ or SQE pump stages are not a variable number. The number of stages is affected by the dash-number as well as the earlier numbers.

 

[Sponsor]

 

[stallhorn]

The well is 200 feet deep, there is some reference about the current pump sitting at 110 feet (which I don't think is accurate).

I talked to the well people, they've never heard of flow inducer. So I think I am going to go tackle it myself.

The softstart thing is what I like about the grundfos, not sure if it is worth it.

Please suggest anything that would be better if you could.

Thanks

 

[Reach4]

https://terrylove.com/forums/index....-minimum-between-flow-sleeve-and-pump.100705/ #2 has info on suitable 3-inch pipe to make flow inducers for an SQ pump.

-----------------------------3 INCH -- more info--------------
for 3 inch for SQ pump
pvc solid sched 40

ASTM 2949 appears to be 3.25 OD, and Fernco seems to call it thinwall.

https://www.napcopipe.com/sites/default/files/media/PL-PS-005-US-EN-0119.2_D2949.pdf

pvc solid sched 30 od:3.25 ID: 3.00 min wall 0.125 ("thin wall")
D2729 Charlotte part PVC 30030 od:3.25 min wall 0.070

Charlotte Pipe and Foundry 3" x 10' Thin Wall DWV Sch 30 PVC Pipe

PVC Schedule 30 Thin-Wall Pipe is for drain, waste and vent purposes only. It is used in gravity fed waste elimination systems. It is for Non-Pressure systems where temperatures will not exceed 140 degrees F. PVC Schedule 30 Thin-Wall is lightweight, non-toxic. There is no rusting or corroding...

www.menards.com

JM Eagle PVC Sewer Pipe 3 in. D X 10 ft. L Bell 0 psi Mfr# 2725 - Ace Hardware

PVC 2729 Sewer Pipe is for sewer and storm drainage applications only. It is used in gravity fed waste elimination systems. PVC 2729 Sewer Pipe is highly resistant to chemicals commonly found in sewage and industrial waste and has a smooth internal surface for minimum flow resistance. It is...

www.acehardware.com

Charlotte Pipe and Foundry 3" x 10' Thin Wall DWV Sch 30 PVC Pipe

PVC Schedule 30 Thin-Wall Pipe is for drain, waste and vent purposes only. It is used in gravity fed waste elimination systems. It is for Non-Pressure systems where temperatures will not exceed 140 degrees F. PVC Schedule 30 Thin-Wall is lightweight, non-toxic. There is no rusting or corroding...

www.menards.com

 

[stallhorn]

Thanks Reach4!

wow.. that's much tighter than I was thinking.. at .15 inches clearance around the pump. I was going to do a 4 inch thin wall around a 3 inch SQ.. any upside/downside for a bigger pipe (4 inch around 3 inch pump)?

I am still undecided on the pump.. is the softstart of the SQ worth it?

 

[Reach4]

wow.. that's much tighter than I was thinking.. at .15 inches clearance around the pump.

Did you follow the part about annular space (the space that water can flow through)? The SQ pump fit into a 2.9 inch space.

any upside/downside for a bigger pipe (4 inch around 3 inch pump)?

Yes. The higher velocity of the water against the pump will make for better cooling. However a 1/2 hp or 3/4 hp pump is not going to generate as much heat. Yet cooler is better. And the flow inducer is cheap.

What is the ID of your well? And how is the casing-- steel, PVC, and how far down does the casing go? Besides cooling, a flow inducer will reduce turbulence against the walls of the well. A 4 inch would do that part. But 4 inch schedule 40 PVC would be 4.5 inches OD.

A flow inducer also would make the pump pick up less sediment, if you do get sediment.

 

[Valveman]

Sorry for the delay. Goulds pumps will drop about 30% in amps when used with a CSV. Grundfos will drop about 50% in amps when used with a CSV. The 3" Grundfos SQ pumps have been around long enough to have a fairly good track record. It is when used with the CU301 controller, making it a variable speed SQE pump that is becomes much less reliable and much more expensive. The SQ with a CSV is known to last a long time. I am not sure the soft start built into the SQ pump is worth it. Doesn't take much to start a 1/2 or 3/4HP pump anyway. In the SQ I would use the 10SQ07-240 at that depth. But the 4" Grundfos model 10S07-12 would also be a good choice, and I think the 4" pumps last longer because they spin slower. Grundfos' own engineering handbook says doubling the RPM will quadruple the wear rate. So, the 3,450 RPM 4" pumps will last longer than the 10,700 RPM 3" SQ pumps.

In the Goulds I would use a 10GS07 at that depth. Pretty much any pump works well with a CSV. Some pumps just drop lower in amps than others. The Grundfos pumps will drop in amps when using a CSV without varying the speed about as much as when using a VFD to vary the speed like the CU301 controller. However, same as with a VFD, pumps are still most efficient when used close to there max flow and Best Efficiency Point or BEP.

You may not need a flow inducer if water flows up to the pump in your well. But a flow inducer will make the motor run cooler and last longer. The tighter the fit, the higher the water velocity past the motor, and the more cooling it will get.