need reccomendations on submersible pump for underground storage tank

[Dolphin]

I am trying to get a well house up to speed that was poorly designed and maintained. The well pump now feeds a 1700 gal underground storage tank. A booster pump (looks about 3hp to me, no nameplate with specs).... it pumps water from the underground tank into 4 pressurized bladder tanks... standard tanks u see everywhere.. maybe 100 gallons max., pressure is set to 60 psi on switch.

Problem is, the system does not get used much, and the booster pump constantly looses prime. I tried a feed hose from the pressurized tank loop into the pumps head and suction pipe, but its "hit or miss", sometimes I prime it, other times, the flow from the garden hose that feeds into the pumps inlet, prob. has insufficient volume vs. the 1.25" PVC piping it trying to fill... Also, the check valve at the bottom of the pipe (about 1 ft from the underground tank bottom) does not seat properly...too much dirt comes up from the well pump, into the storage tank.... I have the underground tank open and empy now, and need to make some decisions on where to go from here...

1) Do many of you put filters on the well pump feed to the storage tank to reduce dirt build up in the storage tank?

2) My first inclination to solve this nuisance pump-prime problem, bite the bullet, ($) and install a submersible pump (well pump) in the underground tank, then, it will always be primed. Hopefully I will only loose maybe 12" of bottom water, which is acceptable in this tank. I can put a large PVC pipe with large holes drilled into it, to keep the pump upright. My thought is, if I take this route, I will never be at the mercy of a priming system, or failed check valves on the bottom of the suction pipe... not fun digging down to this tank, and getting to the check valve in the future...If this makes sense, maybe someone can make a suggestion on the right type of submersible pump... the booster pump is 230V at about 15 amps when I did a quick check. Bottom of tank is maybe 12 ft under ground level. The underground tank is only 5 ft from the storage tank loops, outside the well house.

Since the underground tank has a float, and now maybe a submersible pump, I feel uneasy about covering what we just dug. I would think having quick access to the tank is a good idea. I was thinking of installing a 4ft wide metal pipe (culvert?) over the tank lid and PVC ports. Up to ground level, and place some type of "manhole cover" on it... Is there "access" products like this on the market...if so, maybe someone can provide a link. I can fill the access port with insulation to prevent from freezing. any thoughts would be appreciated on this....I sure see lots of advantages over above ground tanks...

TYIA

[valveman]

Yes I would put a filter on the well pump to keep the dirt out of the cistern. The foot valve leaking is why you are losing prime. Remove the above ground check valve and the pressure tank will keep the pump primed. However, if you don’t fix the foot valve, the pump will then cycle back on when you are not using water to make up for the water lost through the leaking foot valve.

You can lay a submersible on its side, then you won’t loose the bottom 12” of tank capacity. However, keep the sub off the bottom a little so it doesn’t pick up dirt. See the picture. This is a good way to lay a pump in a cistern, but the pump needs a shroud or flow inducer sleeve.

And yes make a lid of plywood or sheet metal so you don’t have to dig to the cistern any more.

[Dolphin]

Thank you Valveman for confirmation..... nice pix, nice approach.... that would work great...
In this situation, I think the well pump in the storage tank is prob. best....
could you please reccomend a pump size, brand, based on what I mentioned above?
and also, what filter do you suggest I put on the well line feeding the storage tank?
well is prob. pushing 30 gpm max. at the outlet... I measured the flow coming out of fire hose we use to fill water truck... of course, this flow rate is when the pressure tanks are exhausted.... so pure well pump.
thank you very much for your very timely and helpful information.....

[valveman]

A 3 HP will do 50+ GPM. That is enough to supply 10 houses. A ½ HP, 10 GPM submersible is all you need to supply the average house. The brand is not that important with that size pump, but I prefer non-corrosive metal or plastic for the pump housing instead of cast iron. Larger than ½ HP might be needed if you have irrigation demands or anything other than the house.

I would use a spin-clean filter or something similar.

[Dolphin]

Thx Valveman...any suggested web sites to buy this 3hp well pump? I have no local suppliers where I am at.. google does not turn up too many 3hp 50 gpm pumps...what is approx. price I should pay?

[valveman]

A ½ HP, 10 GPM submersible is all you need to supply the average house.

Why do you need a 3 HP at 50+ GPM?

[Dolphin]

Well, that is the size of the booster pump that it would replace...... however, that is no justification for replacing it with the same size.... since everything about this installation has had quirks... as mentioned, there was so many different applications the well house was used for since it was built 2 yrs ago.....servicing just a few houses for now, and then the need to fill a water truck increased the demands on the flow rate... hence the booster pump system....

My original premise was.... the booster pump looses prime too easy, and its a major pain to get it primed with the crazy garden hose bypass currently in place between pressurized loop and booster pump (uses valves on both ends of hose to control when pressure is introduced).... I considered re plumbing so the pressurized loop would feed the booster pump and suction line with the same size pipe, 1.25". Then, it would always be primed, cause the garden hose appears to be insufficient flow, but maybe after check valve is fixed, it will be sufficient? Regardless, the problem, as you correctly pointed out, the failed check valve at the bottom of the suction line defeats the prime, and also ends up pressurizing the underground storage tank, forcing the relief pipe to let water escape. This must STOP. As you wrote in a Sticky above, (thank you for the great reference material Valveman) there is two kinds of check valves, ones that have failed, and ones that will fail. Well stated....this made me think of an innovative and long term solution, whereas I can keep the current booster pump in-use. I am curious of your thoughts....

Now that the tank is dug up, and will have easy access from ground level (I will build a wood access port for easy access to all components on the underground tank).... this solves a major future service issue on the tank components / controls (this project sure made me appreciate the value of above ground tanks)

My idea is... use 2" pvc flex pipe on the suction line, starting at the top of the underground tank...at the bottom of this flex line, would be a check valve. I will tie a rope to the bottom of this flex 2" flex line and attach to the top of tanks access lip. Now, the check valve can be pulled up from the top access area for easy cleaning / replacement... tank is maybe 8 ft deep. This will only take a few minutes after the access port is built. Seems this check valve is critical, and requires maintenance, so easy access to it, seems to be the ideal remedy. (this will never be 100% maint. free system, I have accepted that) Since the flex line is 2" wide, I am assuming it will not collapse as vacuum pressure is reduced with wider pipe... I can go wider, such as 2.5"? Assuming this flex hose will not collapse....then.... as a safety measure, I can put a flow switch on the underground tanks "relief pipe"... as, if the check valve fails, the pressurized loop will continuously feed the underground tank, and the relief pipe will flood the area....since quite often, no one is around to visually see this.... the flow switch kills power to the well pump, which is the source of pressure to the bladder tanks. Now the flood is just a small mess vs. an unwanted lake.... my goal, is to have a well house that is always usable, (water to houses and water truck) while eliminating the risk of a flood. This also allows me to keep the current booster pump in play, vs. installing a well pump in the underground tank to replace the booster pump (my original thought after frustration of loosing prime and no access to that suction check valve) Seems now, with a maint. system in-place on that critical suction check valve, a new emergency cut-off system installed, I am thinking, leaving the booster pump in place is both lower cost, and a better long term approach.

Any flaws in this approach?

[valveman]

2” suction is plenty large. You just need pipe rated for suction use, which has a spiral wind or something to keep it from collapsing. If you are still filling trucks then you might need the 3 HP. It is way overkill for a house though. And you need to keep the four big tanks or use a CSV to keep it from short cycling.

[Dolphin]

Thx Valveman.... I checked with the flex PVC dealer, they claim the 1.25" flex pipe can withstand to 27 in. of Merc. before collapsing, so, way overkill , no reason to jump to 2" flex pipe.... so seems like a sensible plan to make that check valve accessible for service... and, you did not air any objections....

fully agreed on the 3hp pump...if it was NOT for the water trucks that gets filled a few times a week... I would abandon the underground tank and booster system... the well pump and 4 bladder tanks is more than sufficient for the few residences, or even a few additional ones.