Shallow well pump performance?

[the old grind]

Since I'm not getting the flow I'd hoped for from < a dozen ft of suction head I'm drawn to suspect something throttling-back my flow below ground, like a clogged/corroded pickup screen. Nothing is interfering with the foot valve, and it works ok. I still don't seem to be cavitating or drawing air, as released from the button on the filter housing every other day or so and with only a few cc from each burp with either pump in place.

'Worst case scenarios' include sinking a new pipe (~15' max to clay base layer) and/or digging for an outlet from the cistern that I can tap into for a 'sub'. First, I have to see what part(s) of the original setup can be used. I haven't ruled out creating a replacement for the cistern, sort of a septic-in-reverse w/lines laid out along shore several yards back from the waterline and up to 100' long with a concrete distrib box or poly ejector crock for a sump. (they'd have to be pretty tall to house a sub)

MY 'sub' of choice so far is Grundfos 3" 5SQ05-90. Its way of performing on par with 4" pumps is to use a 10k rpm motor, and I can easily go two-wire w/g with the 230v model and no controller needed. 'SQ/SQE' is said not to require a cooling shroud below 30C/86F and only fractional GPM for continuous running. That said, I could still shroud to lower intake if the pump is tall for my well or its tie-in from a cistern. Carbide over ceramic thrust bearings per stage is supposed to minimize thrust wear with its floating stages.

I'm cleaning and re-applying 50/50 ATF & acetone to the 4 1/4" pipe's top thread every few hrs to uncap it. (working better than Kroil or PBlaster, btw) Depending on what's in there I'll know what options I have.

 

[buickanddeere]

I'm not sure if you and I are calling a stage the same thing. But a four inch submersible pump has impellers of less than 4" in diameter. The pressure that any four inch impeller can make is dependent on it's diameter and it's speed. At 3450 RPM's a 4" impeller (which is around 3-1/2" in diameter) can make very close to 14 lbs. Each subsequent impeller in the stack adds another 14 lbs.

I'll try and find the info but your data is making more sense at one atmosphere per stage. I may have been thinking of a specalized 3-1/2" pump with a VFD and higher rpm ??? In any case it is possible to have too much of a good thing or too many pump stages for the application.

 

[Valveman]

The SQ pump is OK if you need something that can fit in 3" casing. They will also start easily from a generator or battery. But they cost more than a standard 3450 RPM pump, and the 10,700 RPM increases wear rate. From Grundfos' own engineering manual they say "doubling the RPM of a pump will quadruple the wear rate". So tripling the RPM would really increase the wear rate. Using the CU301 controller to make the SQ into a variable speed SQE increases costs and reduces dependability even more. Constant pressure pump controls are a good thing, but there are better and simpler ways than variable speed pumps to make that happen.

 

[the old grind]

My 'casing' is 4 1/2" at the threaded plug I'm working to remove. I'd gladly consider a 4" sub, but I expect to want to shroud it for top-filling from the cistern, and I'd need clearance around the shroud, too. A lot depends on what I find 'down the hole' and whether I could use it for a sub if I can't get better results from the conventional SW pump and screen.

That said, initial cost and short pump life don't scare me if my drop pipe is to be <10' long, and so easily accessible. I should add that during our last serious power outage (2 1/2 days, temps in the teens) I felt no need to haul out the generator for water. I turned 2 stove burners on to med, lit a few candles downstairs in the workshop and three to read by. Temp indoors never fell below 50F as I waited it out.

I've been familiar with VFDs for decades as applied to 3ph shop machines (mills, lathes, my smaller mill has OEM VFD) and feel they are more complicated than I'd be happy with in the long run for this use. Since I now have a CSV I plan to incorporate it in future plans too, esp if better pump/well performance makes setting the exact output pressure easier.

I do want to stick with 30-50 sw and a 40psi output adjustment. Since final tank draw-down would be several gallons before the pump kicks on it'd seem to favor replacing my tank with a smaller one. (IME, with only yearly pressure checks a genuine Well-X-Trol will outlast several pumps, Flotec maybe 10 yrs w/same)

It all comes down to what I uncap or dig anew. Nice weather is still in my side if I fire up the mini-BH and make a big project out of this by digging away. :laughing:

 

[the old grind]

OK, the plug is out and I don't know what I'm looking at just yet.


I lowered a bob from the top. It went 36' down and clunked on a wet-looking bottom, then came up dry. Note that the top of the pipe is atop a steep ~4' slope and no more than a foot higher than the pump. Of my half-dozen bore/inspection cams none will reach more that 15' so I can only guess that it's drilled well into the clay, but not drawing water. The hard bottom is far below the nearby/static water level on shore <50' away, to a depth beyond a S-W pump's ability to draw. (35' below the pump!)

I don't get why the metal pipe is isn't filled with water, or why it's even there. I suppose it could be from a failed attempt to drill, but IMO there's a lot of weird to guessing why it's all metal, fully cased, so deep, and hard/'dry' at the bottom. It seems to have nothing at all to do with my well or water supply. :confused3:

I do have room to dig into or around the stone pit, but with 16 sq of siding to put up (by myself) It'll have to wait for Spring. At least I'm doing my 'bucks-worth' better since upgrading the pump. t o g

 

[Egon]

Since I'm not getting the flow I'd hoped for from < a dozen ft of suction head I'm drawn to suspect something throttling-back my flow below ground, like a clogged/corroded pickup screen. Nothing is

interfering with the foot valve, and it works ok. I still don't seem to be cavitating or drawing air, as released from the button on the filter housing every other day or so and with only a few cc from each burp with either pump in .

Filter pack in drawdown cone.

 

[the old grind]

Filter pack in drawdown cone.

Non-reversing tremmy pipe separated from the waneshaft housing, then? I have no way to measure marzelvanes/hour in real time, so do I have to ship it all back for refit? btw, I've heard they're now using TiCN coating on face seals, so maybe I'll have them all replaced. (..???..)

Egon, whatever I have for point/screen I couldn't guess where it is, how deep, etc ... Is that something I should add, or should find and fix?

I'd have all Winter to design a new cistern/sump for a submersible and lay out a trench to the pump room. I can use the 2" pond pump or the sidelined Sta-Rite to assess flow, once dug. Maybe I can hire another $15/hr 20 YO who lives with Mom to stand around, with one hand in pocket and the other checking his phone every ten minutes and watch me (as usual) for a confidence boost. Naw, that would cost more in the long run than calling a well driller to go deep and to code. :laughing:

If the metal pipe (4 1/2" ID) is clear and closed at the bottom (it's not filled with groundwater yet) maybe I can tie it into the stone pit as I thought had been done and use that for a sump after all. There was condensation on the underside of the plug but no corrosion evident in the pipe, so it looks ready to use and might get me there with less backhoe work.

Pretty sure I'd have to go 3" vs 4" on a 'sub' to allow room to shroud/sleeve for top filling in a 4 1/2" hole. That could put the intake easily 20' below static level, even at seasonal low, as now.

I have a plan to extend the reach of one of my inspection cams to get a better look at what's at the bottom of the pipe.

 

[Egon]

The present area that well bore is drawing water from is getting plugged with fines and limiting the water flow.

At twenty or so feet deep think about moving the well location. A hand operated post hole digger and water flushing should get you a hole for the casing. Then drive the well point.

No guarantee. .

 

[DieselBound]

My head is spinning from reading all of this (it's all over the place) :confused2:

Nowhere did I see anyone verify the recharge rate of the water source. This is important. Assumptions must not be made here. Any well/water person wants to know what the recharge rate is in order to match up the appropriate solution. AND, you need to know what your casing capacity is (applies to hand dug wells too).

To figure out how much casing capacity you need to know depth as well as static water level. It was already mentioned how to measure depth. For static take the small float-able item (fish bobber works well) and tie it to the end of the line and drop down until the line goes slack- measure and you have your static. Knowing the volume/capacity is then factored in how much you can draw (and set the pump if you're doing submersible).

I've got a 38' well: somewhat newer so it's fully documented. It was not in use when I bought my property. Ended up rehabbing this well so I got a pretty good education. Output was recorded at 30 gal/min; I ran a 10 gpm pump for 24 hrs straight and had NO shortage of water, so I figure that output is still pretty high. I only really needed to know static to set my pump- no concerns about drawing down the static (pump was properly matched [under recharge rate]).

Pushing water seems better than pulling it (which is why above-ground pumps that pull water can only theoretically pull down to a level of 26').

I've researched all kinds of home water systems, even rainwater collection into cisterns (from roof tops and from lean-to-like structures specifically built to provide a surface for the purpose; created a spreadsheet to assess depletion rates given month-over-month rainfall collection abilities). I mention this because sometimes one might consider a lower-rate charge/fill to a larger storage, with the larger storage being sized to meet whatever draw needs that one has (be prepared to learn how fast one can use up water!).

Well professionals can sometimes frack wells such that you open up better channels. This may open up paths through gravel instead of sand. If sand isn't a huge problem then look to utilize a spin-type trap filter (I've got a Lakos twist-lock, though I really probably didn't need it because I don't have much in the way of sand- it was more for peace of mind).

 

[the old grind]

DB, the oddity with the pipe is that it terminates so far below static level and I have no idea how a S-W pump could draw from so far down. In that area (50' from the beach) I can find groundwater easily with the Terramite or with the Earthquake PHD and no extension on the auger. There's 15-20 ac/ft of water minimum in this former sand pit, according to seasonal level. I've live within 1/2 mi of here since '89, 15 yrs here, and can guess from familiarity and by pond level whose sump pumps nearby are running at any time of year.

The bob I dropped (to 35' lower than my pump height) went easily to the bottom, hit something solid, and came up dry. Perhaps a pitless adapter is what's there, but that's 25' below static level anywhere near here. According to county records on a well drilled up front in '95 there's a dense clay layer not far down and 50' - 60' thick. It starts <10' below my lower lawn, the top of the stone pit, the patio and basement floor, and obvious on the pond's bottom where there are sidewalk-like exposures of clay that nothing ever grows on. (avg depth <6' was limited by digging ~to clay eveywhere)

So, if there's a PA that far down w/sump below it was bored well into the clay and if also connected to the pit or whatever its point is fed from that's at nearly one atm higher than my static level. IMO, that's like 'ersatz-artesian' and explains why I never draw much air or lose prime, but that a S-W pump works at all. It could literally 'pressurize' a point that far down and I'm back to drawing 'net' from much closer to static level after all. :scratchchin:

As to drawing down excessively, I can come home from a week away and jump in the shower or wash the car to see water pressure flag just as the pump comes on, it recovers flow/pressure no more noticeably quickly than when doing a second consecutive load of laundry or amid a vehicle washdown. Total flow/refill is never very high/fast but is always consistent regardless of use.

I'm working on getting a camera to the bottom of the pipe. If there's a PA there then what I described above seems to make some sense. It also means that there likely won't be much tinkering with what's there, being ok for now, and being willing to drill anew to the aquifer below the clay layer. That would put a submersible easily 60' below my static, as is the norm locally and it appears to bottom-fill from a typically 170'-190' bore.

btw, water from the lower aquifer here may draw from salt deposits that seep into say every other well within a mile. (Green fixtures common w/o softener installed) What I get from the shallow well is the most calcium and water-spotting water of anyone around.

Still learnin', still explorin' ....