Hey guys, for the 3rd time in 12 years my deep well pump has failed leaving me with an opportunity to restructure my system. I have moved from the original 1.5hp pump down to a 1hp and now will drop again to a 1/2 hp. As I learn more about pump curves and flow I realize that the pump was drastically over sized and wasting $$$. Please tell me if this is a good alternative. Well is 500' with 35' head. I need 10 Gpm for the geo and 5 for the house. my draw down is nil if I don't draw more than 6gpm. I am now feeding my geo with my domestic tank at 50 psi. I propose that I install the new deep pump and set it for 10-12 psi and feed the geo with this. from this feed, a booster to 50 psi for domestic. any recommendations on pumps? I was thinking SQE at first but I may not need the expense if I go this route. Any input would be awesome. Thanks Rick

Use largish pressure tanks and note that for short periods, the heat pump is OK with somewhat less than the nominal GPM. With the pressure tanks delivering short term needs, the house might also be OK with less than 5 GPM continuous. So don't design for the full/continuous 15 GPM @ 10 psi.

OTOH, what happens if the heat pump runs continuously for a long period and the well is only yielding 6 GPM? At some point, you are pumping from 500' (inefficient, requires a large motor) - and then it goes dry. Consider a hybrid standing column design where 4 GPM is returned to the well (perhaps conditionally) and the well level never drops much. Then 1/3 HP is enough.

I'm curious - were you able to tell exactly why the pumps failed?

Sorry, I should have been more specific.......The well is an open loop standing water column. draw from bottom and return to top. I can pull as much as needed thru the geo because it returns to the well. My head will very rarely go more than 100'. And I would love to down size to a 1/3 hp pump. Need help picking pumps. Brand and model would be great. I have no experience with booster pumps and have no idea what is good or bad as far as brands

Ah. The idea that soft-start pumps (eg, SQ/SQE) experience less wear sounds plausible, but I don't know of any hard data. Most also run at high RPM (sounds like it would create more wear). Maybe the 15SQ05-110. Booster pump shouldn't be so critical (far fewer hours, easy to replace).

Also consider the single pump, dual pressure system used here and here.

I wonder if enough temperature stratification occurs that drawing from near the top (say 100') and discharging to the bottom would noticably increase Winter HP efficiency.

Well, after reading all the info I am going to get a grundfos 22SQE-05-80 and the cu301 controller. I will build a relay center to fool the 301 into thinking its pumping 55psi (but only 15psi in reality) during geo operation and actually pumping 55psi when the geo is off. I will also add a pressure switch on the house that will remove the resistor that fools the unit when the geo is on and the house pressure falls below 40psi allowing it to run at 55psi until the house is satisfied. this should be easy...ill post my results
xs

to answer jonr, the pumps may have failed due to being too low and picking up some sediment running the impellers. This last pump may not have failed. the pressure switch was allowing 240vac to the pump but restricting amperage. unfortunately, I already had it out and its 1hp. I wanted to down grade the hp to .5 hp anyway. this gives me a reason to become more efficient.

the pumps may have failed due to being too low and picking up some sediment running the impellers.

Sounds like another reason to put the pump high and the discharge low (if you have room).

I am going to get a grundfos 22SQE-05-80

You need more pump for a single pump system. I get a worse case of 55 psi (126') + say another 74' for lifting from the well and pipe losses = 200' @ 15 GPM. So the 15SQE10-220. The 22SQE-05-8 tops out at 120' - it can't produce 55 psi, even at 0 GPM. Don't worry about it being 1 HP - once you have variable speed, moderate over-sizing is OK (actually, it will probably last longer).

Well, I read your post a bit late and ordered the 1/2 hp last night. I am going to try to catch the shipper before it leaves and see if I can upgrade it. The system should hold static of 30' unless I exceed the replenish rate of 6gpm. 2 showers and a sink running is just getting to 6gpm so the only thing that could impact it would be irrigation. The irrigation is set at 5gpm per zone. I can set it for middle of the night to reduce the risk of it impactin the system.
Because I had an issue, I went to lowes and bought an off the shelf 10gpm 1/2 hp pump and thru it in in the mean time. No issues so far and it's set to 60psi. I'll upgrade the pump if possible, but if not I'll be creative with usage. Thanks for all your help jonr

Xs

I upgraded to a larger pump, Grundfos 15SQE-07-180. this pump should deliver to a comfortable depth and still exceed my gpm through the curve. I realize that it is close on gpm but that is at 180 ft. I will rarely pump down to a level that low.

You're welcome. You should be fine with that pump. For other readers, note that the pump rating is the depth it has to bring water up PLUS the pressure you need (converted to feet) PLUS pipe losses.

Set up question, I will be coming from my well to the house with 1-1/4 pipe. it will tee in the house. Left side to the geo, right side to the house. right side will have a check valve, 80 gal well tank, and will run at 55psi. Left side will go through the geo and run at 15psi (transducer will be located on this side). I will set it up to run at 15psi when the geo is on, but it will go through a relay connected to a pressure switch set at 40/55 on the right side of the tee so if the house fall below 40psi....the pump will pressurize both sides until 55 is reached then revert to 15psi. here is the question

do I need a second well tank on the left branch? I am thinking a 30 gal tank on the left branch.

I've always seen in with a 2 gal tank and given that it's for geo, I don't see a reason to go larger. The bigger the better on the other side.

You will have a pressure regulator to reduce the "sometimes 55 psi" to 15 psi before it enters the geo?

right now my geo runs at 55 psi all the time, I did not consider a regulator because I don't want to restrict the flow more than I already have(10gpm). I think running the geo for a few mins at full pressure isn't a huge deal breaker and there are no extra parts to break.

Without a regulator, more pressure causes more flow. So if you currently apply 55 psi and you get the flow you want (10 gpm), then you aren't going to get adequate flow at 15 psi. Or vice versa - the right flow at 15 psi will mean way too much flow at 55 psi - so your 15 GPM figure (house + geo) is way low.

A properly sized regulator set to 15 psi won't restrict flow @ 15 psi significantly.