Adding a 240V inverter for well pump

[Rick_in_MT]

I see a Grundfos 15SQ05-110-115V, 15GPM, 1/2HP, 115V, 2 Wire, 96160169, 3" Stainless Steel Submersible Well Pumps
Is there any problem that my casing is 4" not 3"? I can understand the reverse would be a problem...

 

[tomy2]

dang, must be from a proud driller/installer for that price. Here is the 110' 120v 10 GPM for under $867 with shipping. This is the company I got my pump and wire from (aquascience.net). The 160' always seems to be back ordered or delayed. Its a very common one to buy.

Grundfos 10SQ05-110-115V, 10GPM, 1/2HP, 115V, 2 Wire, 96160166, 3" Stainless Steel Submersible Well Pumps

By the way, Grundfos does not have support. You are left with whom you buy from. By some serious effort and luck, I have actually talked with one of their engineers trying to get a question answered. It was a miracle.

Yes, that's where I bought mine. good to see that they are keeping their prices down, nobody else is.

 

[ChrisG]

Pulling out my Franklin 1/2hp pump and replacing with Grundfos 10SQ07-200 was the best decision. Did the work myself as it was only 100ft deep. Well worth the effort. Franklin took 9kw inrush to start. Grundfos starts at 500w and goes to about 1200w over 2 to 3 seconds.

 

[Ampster]

Is there any problem that my casing is 4" not 3"? I can understand the reverse would be a problem...

Not that I know of but I have no direct experience with wells. I have enjoyed some Youtube videos to get some knowledge for my nephew who has a well. if your pump is on plastic pipe and only at 80 feet you might be able to pull it by hand using two people.

 

[sunsurfer]

Not that I know of but I have no direct experience with wells. I have enjoyed some Youtube videos to get some knowledge for my nephew who has a well. if your pump is on plastic pipe and only at 80 feet you might be able to pull it by hand using two people.

Coming up there is allot of water weight in the line to remember. I would at least tie it to something while coming up incase you get tired and a wheel to prevent the pipe from kinking. Also, some (most) areas you may be breaking the law pulling your own pump but that doesn't stop allot of people from doing it...just FYI.

H2O Mechanic has some really good vids;

 

[sunsurfer]

Word of warning to anyone tinkering on a well/pump;

If you have the top plate with 4 bolts, DO NOT LOOSEN THEM ALL THE WAY! There is a split plate below the rubber disk that will FALL into the well. Just loosen them to relax the rubber and it will pull up. This is a common mistake that causes lots of problems.

 

[ChrisG]

Word of warning to anyone tinkering on a well/pump;

If you have the top plate with 4 bolts, DO NOT LOOSEN THEM ALL THE WAY! There is a split plate below the rubber disk that will FALL into the well. Just loosen them to relax the rubber and it will pull up. This is a common mistake that causes lots of problems.

Most have a pitless adapter to feed the house far below the frost line and just simple cap on top. Make sure you have the right size tool and it’s snug for the pitless so you don’t drop the pump.

 

[Rick_in_MT]

So. how can I tell what my current GPM is on my 230V pump? And if I should get 10 or 15 GPM in the Grundfos pumps? And does it even matter since I run a pressure tank? The cost difference between the two is only $65, $799 vs. $865, so that doesn't matter much. Will I even notice the difference or can the money go for cable and hardware parts...?

 

[sunsurfer]

So. how can I tell what my current GPM is on my 230V pump? And if I should get 10 or 15 GPM in the Grundfos pumps? And does it even matter since I run a pressure tank? The cost difference between the two is only $65, $799 vs. $865, so that doesn't matter much. Will I even notice the difference or can the money go for cable and hardware parts...?

The big difference will be on power needed for the extra 5 GPM. I would estimate you would go from 1000 to 1500 watts as an example. If your well flows good, I would go for the 15 GPM because I like having extra for doing multiple things at once. Example, showering while filling the washer and irrigating the garden. Not sure how "off-grid" you want to go. Its all about life style mixed with available options. You should give aquascience a call and see if they can help you figure the pumping total height. I think you would be either the 110 or 160

You should be able to measure the output close enough by just running it with a stable pressure and timing a bucket fill.

 

[ChrisG]

So. how can I tell what my current GPM is on my 230V pump? And if I should get 10 or 15 GPM in the Grundfos pumps? And does it even matter since I run a pressure tank? The cost difference between the two is only $65, $799 vs. $865, so that doesn't matter much. Will I even notice the difference or can the money go for cable and hardware parts...?

You should do the calculations for total head to figure out the pump to get and plot against the manufacturer flow rate you need. There are simple calculations for total rise, pipe size, pressure tank to get you total head. I did the math then called aqua science where I ordered the Grundfos and barb from. They confirmed my calculations which is giving me 10.5/gpm at 60psi max pressure for a 3 bedroom 2.5 bath cabin. 10.5gpm was more than enough as I don’t do any outside irrigation.

 

[rhino]

The big difference will be on power needed for the extra 5 GPM. I would estimate you would go from 1000 to 1500 watts as an example. If your well flows good, I would go for the 15 GPM because I like having extra for doing multiple things at once. Example, showering while filling the washer and irrigating the garden. Not sure how "off-grid" you want to go. Its all about life style mixed with available options. You should give aquascience a call and see if they can help you figure the pumping total height. I think you would be either the 110 or 160

You should be able to measure the output close enough by just running it with a stable pressure and timing a bucket fill.

Having a larger pressure tank can also mitigate needing bigger pump. I replaced mine with a 30 gallon pressure tank set for 60psi if I recall and don't notice any issues taking shower and doing laundry at same time for instance. It is a 10GPM grundfos.

 

[Firstrapid]

Use the well log to see what the driller noted the well output to be in GPM. If no we'll log is available there are several U tubes on how to measure this. Once you know the GPM of the well you need to find out the static level of the water in the well. The static level added to the height of the pressure tank will tell you how far the water needs to be lifted so no matter how deep the pump is the head remains the same. Add the pressure the pressure tank bladder pressure and you have the number to apply to the pump sizing chart to determine the size pump you need. Don't pump more because you may run the well dry. Grundfos is the best!

 

[sunsurfer]

This thread just keep getting better! Lots of great info. I would be curious if anyone knows about sizing efficiently Grundfos (or other) in relation to the rating. What I mean if its a 150', does that mean you want to hit the top pressure of your tank right at a 150' head or stay below???? The graphs show a wide range but I have heard you want to be close as possible in the sweet spot. Hope someone has some good insight on this, or if it even matters to much. If its just a 10% thing, etc.....

Also, I think there is a factor that has to do with the thrust bearings preloading but I just don't remember.

 

[ChrisG]

I first did several bucket tests to verify my GPM using the drain tap just after pressure tank. Knew I needed 10GPM to match current pump.

Next calculate total rise (mine was 90ft rise in pipe to horizontal run to house) so 90ft head PLUS 60psi tank (60x2.31=138ft head) for a total of 228 ft head. I did not factor in pipe loss or a few elbows exactly so I just used 230ft total head.

Then started looking for pumps. The 10SQ07-200 was about a perfect match for 10GPM at 230 head according to this chart. Actually could have gone up one more size but it wasn’t in stock. It pumps for about 54 seconds to fill a 45gal pressure tank to 60psi. Think the rule is try to get close to 60 second run time to keep motor cool which seems factored into grundfos calcs.

 

[MichaelK]

So. how can I tell what my current GPM is on my 230V pump?

I bought something like this. I just plumbed it inline with the pipe that goes up to the storage tank.
You can get one in gallons, cubic feet, ect. Has been very important to me in drought years.

 

[BarracudaBob]

I was looking at using this for my 1.5 HP well (above ground) and pool pump:

SPI 2200TL2-HV The Growatt SPI 750-4000TL2-HV Solar Pump Inverter

https://signaturesolar.com/growatt-2-2kw-3hp-l-spi-22000tl2-hv/