Vertical 1HP Jet Pump pipe stand? NPS threaded cast feet in the base volute? How to secure?

[Clog]

I have a vertically mounted multistage 1HP jet pump hovering directly above a double pipe (1" drive, 1-1/4" suction) well of unknown depth.

The previous owner/installer (hereinafter "PO") decided to elevate this pump 16" above the concrete pad that the 4" well casing is flush with.

There are three mounting feet with threaded holes in them that are cast into the base volute of the pump. The thread diameter and pitch is 1/2" NPS.

The PO used 3/4" bolts through these holes, which pass through the holes in the cast feet clearly, and obviously without thread engagement, and these bolts were threaded into 3/4" nuts that were welded to the inside of 2" square tubing stood on end, to serve as legs. Then he welded one angle tab to the bottom of each leg, with a hole for studs that were cast or drilled into the concrete.

Two of these studs rusted and broke off at the surface of the concrete. All three angle tabs rusted and are now as thin as paper, and I found the well pump was being retained by only one leg that was still mechanically fastened to the concrete pad. The other legs were just along for the ride.

The "ride" is every time the pump cycles, the torque from the twisting of the motor yanks axially against the final leg. This torque, combined with corrosion from a poor selection of materials, is why the two legs failed.

An additional problem with the bolt and welded nut inside the tube mounting arrangement is that the hex heads of the bolts were all grounded to be round so as to clear the body of the pump, so there is no way to put a wrench on the bolt head, and there is no way to access the nut without unbolting the leg from the concrete and turning the entire square tubing leg. But the angle tab at the bottom of the leg then collides with the suction and drive pipes, or the protruding lip of the well casing, or the well seal cap, as soon as it is rotated past 180 degrees. This improvised well pump mounting system leaves much to be desired, and is neither professional, workable, standard, or anything that the original pump designer would likely have imagined.

In seeking to solve this problem (among many other problems with this well) I'd like to utilize the 1/2" NPS threaded holes that are already tapped into the three feet of the base volute casting. If the pump manufacture added a production machine tooling expense to thread those holes, there has to be a good reason, and I'd like to utilize what the factory originally intended when incurring that expense.

The first question I have is... what should be threaded into 1/2" NPS (straight) holes that would serve as legs to elevate the pump?

Can 1/2" NPT (tapered) male pipe nipples (serving as 16" tall legs, with pipe flanges red headed to the concrete pad acting as feet) be screwed into 1/2" NPS (straight) female holes in the cast mounting ears of the base volute, with no expectation or requirement for liquid "sealing", but with cautionary concern for the general propensity of castings to crack... especially if mis-threaded, and subject to daily cycles of starting torque?

I reached out to the pump manufacturer (PentAir) who said that back in the day there was a different design (much larger, and more expensive to manufacture due to additional materials) combination seal plate adapter flange (sold separately from pump) that included "3 NPS bolts" that threaded into the base volute. "Time changes, material cost goes up, seal plate got smaller. And it was feasible to add into machining the 2 standard thread bolts to secure the pump to the smaller seal plate we use now. And the tooling (for the base volute) has not been replaced so the current (base volute) still has these (1/2" NPS) threads."

The PentAir multistage jet pump model (and identical equivalents under various brand names) is:

SEARS 390.253251
STA-RITE MSE-7
MYERS MVPH-100
FLOTEC FP4432

I don't know why the PO elevated the pump 16". I'm assuming there is a reason that is likely at the bottom of the well, of unknown depth.

The well pumped water, until the pressure switch melted from overheating, which was likely due to the captive air pressure tank not holding any air.

Assuming that the bladder failed inside that tank, I bought a new tank, and a new pressure switch, and this project started with just replacing those two components, along with a new pressure relief valve for safety, and all new piping between the two for good measure. But I could not ignore the fact that the pump was standing literally on it's last leg.

My hope in this post is to learn whether or not it is OK to use 1/2" NPT (tapered) pipe nipples as legs, pre fitted with pipe flanges as feets that will be secured with red head fasteners into the concrete pad surrounding the well casing, with the tops of these NPT nipples screwed into the bottom of the cast feet of the pump itself, which have female 1/2" NPS (straight) threads.

Alternatively, I am open to other pump mounting methods that might be more suitable. The slightly offset adapter flange attached beneath the pump extends lower than the cast ear feet of the pump's base volute, so the casting ears cannot be set directly on the concrete pad. Nor can the adapter flange be sunk into the well casing, as the well casing is only 4" in diameter... just wide enough to fit the drive and suction pipes, but not the offset body of the adapter flange.

Any and all advice would be very much appreciated.

Thanks!

Tagging: @Valveman

 

[Valveman]

A picture would have saved me having to read a book this morning.

The pump needs to be mounted to the casing adapter. Legs of any kind will have the same problem with torque.

 

[Sponsor]

 

[John Gayewski]

Use threaded pipe and fill it with cement of some type, or epoxy. I think a flange adapter would be ok mounted to the concrete but 16" is too high for my liking. Some kind of water shed for the flange feet/ concrete connection would probably help a lot.

 

[Valveman]

Extend the casing.

 

[Clog]

A picture would have saved me having to read a book this morning.

The pump needs to be mounted to the casing adapter. Legs of any kind will have the same problem with torque.

Where can I find such a casing adapter?

I invested many man hours over a week's period of time analyzing image searches of vertically mounted jet pumps, as well as scoured all the local plumbing and farm supply houses, as well as copious amounts of internet searches, and have struck out.

Sorry for not posting photos initially. I keep forgetting how to.

Above: Original legs. Only one remained attached.

Above: Nipple, Union, Nipple, Thick Style Floor Flange leg ensemble. Unions are to ease future pump servicing/removal.
Also showing 6" well seal that is too large for 4" well casing, and was just sitting on top of concrete pad without "sealing"
Also showing existing offset 2 pipe adapter under pump base volute. This adapter is too large to nest or sink inside well casing.
(Drive pipe nearest to camera)
Nipple length is 8", to match original 16" legs. After assembling this mock up (leg piping not tightened), it seems that 6" nipples would be better suited, so these 8" nipples will be swapped out for 6" nipples on final reassembly.

Above: Full view of Adapter, that does not incorporate, coordinate, or cooperate with any 2 pipe well casing seal or mounting cap that I have been able to locate online, on the ground, or offshore.

Note: I removed the worm gear clamps that formerly secured the black (plastic) well pipes to the gray barbed (plastic) fittings because I was trying to remove the pump. I have thus far failed to get the black pipes to separate. The suction pipe can rotate around the gray fitting, but the Previous Owner had mangled the hex on the fitting, and I'm concerned about messing with it. Suggestions sought on how to get the pump off of these pipes, so that I can improvise an expanded seat for the well casing seal.

Above: Temporary brackets added to prevent well pipes from dropping, in the event that I am ever able to get the pump separated from the well pipes. Super thick floor flanges also shown.

 

[Valveman]

Here is a link for a manual on that pump.

https://www.pentair.com/content/dam/extranet/web/nam/sta-rite/manuals/sta-rite-ms-series-manual.pdf

Incredibly it shows an installation just like yours. But it shows the pump/motor just hovering above the well magically. A casing adapter would not work without a packer, and they only make them up to 3" casing anyway. Installing legs maybe your best option. I would find some way to make it more of a tripod with the leg farther apart to handle the torque. I think that is a bad way of installing it for several reasons. One of which is that the well is wide open to critters.

You could use a 4X1 1/4X1 well seal to seal the well and hold up the two pipes. Then just get a horizontal convertible jet pump to sit on the floor and plumb to the two pipes.

You could save yourself a lot of trouble by pulling out all that pipe and sticking in a submersible with a proper well seal.

 

[John Gayewski]

I wonder if you could start with smaller nipples coming from the concrete. Screw those into a tee. That could/ would make a wider base and give you the option of making a frame to help support the pump. I actually don't have a real clear picture in my mind what configuration would be best, only that there would be some options if adding thr tees.

 

[Clog]

I've read the sticky thread on Submersible Pumps and Multiple Check Valves about 4 times.

Still, I have a question, and since that thread is closed to further comments, I'll ask it here:

In NON submersible, above ground Jet Pump applications with double drop pipes leading to an Ejector Assembly having a foot valve at the bottom of the well (60 foot pipe depth), should a check valve be added, or is the foot valve the only valve that should be used to keep the vertically mounted directly over the well jet pump in prime?

 

[Valveman]

With jet or booster pump you need a foot valve at the bottom of the well, or a check valve at the top of a well point.

 

[Clog]

With jet or booster pump you need a foot valve at the bottom of the well, or a check valve at the top of a well point.

Just confirming the key word being "or"?

(as opposed to "and")?

 

[Valveman]

Yes OR not both. Foot valve only is best. But a foot valve won't fit down a point well.

 

[Clog]

Thanks for the confirmation. The current foot valve is free, clean, and functioning, so that will remain the only check valve.

New sub question: Barbed Insert Fittings threaded into cast iron

Schedule 80 plastic or brass/bronze?

Where the well piping is 60' of continuous flexible black plastic rated to 100 PSI, and where the ejector jet assembly and the pump adapter are cast iron, which type of 1-1/4" threaded to barbed insert fitting provides the best seal over time?

 

[Clog]

Another question... that was resolved by the manufacturer.

 

[Reach4]

I would strongly suggest you consider a submersible pump for your 4-inch steel-cased well. A 1/2 hp SQ pump would do wonders. No priming. More efficient. Quiet.

I would put a flow inducer on this 3 inch pump. If interested, I could suggest materials.

The huge downside is you have already invested a lot of time and money into your jet pump.

 

[Clog]

The well is 4" cased, but not 4" steel cased. It is 4" plastic cased, and as I peer down the hole, it appears that the plastic well case pipe curves a bit here and there. This may interfere with either the lowering or raising of a submersible pump, depending on the length of the pump and the radii of the wandering curves in the casing.

You are correct, I have invested a lot of time and money... about $1,000 thus far... but this isn't my jet pump. It is my elderly neighbors well and pump, and what started as her asking me why I thought her well stopped working, immediately turned into me shutting off her power, as the pressure switch was a melted blob of plastic and metal, with all the insulation cooked off of the power supply wires and the wires leading to the pump.

The previous "handyman" she paid $120 an hour for, supposedly "fixed" her pump by priming it with city water and starting it up for her. He didn't bother to look into why the pump wasn't working right in the first place (captive air tank bladder busted, pump was constantly running, etc). I was so upset at the $120 per hour handyman that I promised her that I would fix it for free,

I appreciate (and have learned from) the twice echoed suggestions to switch to a submersible pump, but this project will have to carry on in the direction that it started, using the neighbor's original configuration.

I was able to resolve my question in Post #13 after calling PentAir for clarification. Turns out, the so called "Special Adapter" is nothing more than a barbed fitting, not a venturi. The venturi is built into the cast ejector assembly.

 

[John Gayewski]

Thanks for the confirmation. The current foot valve is free, clean, and functioning, so that will remain the only check valve.

New sub question: Barbed Insert Fittings threaded into cast iron

Schedule 80 plastic or brass/bronze?

Where the well piping is 60' of continuous flexible black plastic rated to 100 PSI, and where the ejector jet assembly and the pump adapter are cast iron, which type of 1-1/4" threaded to barbed insert fitting provides the best seal over time?

It's almost never better to use threaded plastic vs bronze/brass. An exception would be chemical environments. Especially on a vibrating pump a metal connection would be better. Even better would be a stainless flex connector.

 

[Valveman]

It's almost never better to use threaded plastic vs bronze/brass. An exception would be chemical environments. Especially on a vibrating pump a metal connection would be better. Even better would be a stainless flex connector.

I agree. If nothing else it is hard to get the worm gear clamps tight on plastic insert fittings. SS or brass is the way to go, and extra long barbs are good so you can use more than one clamp.

 

[Clog]

Just to update...

I was able to "seal" the 4" plastic casing whose opening was flush with a concrete pad, by locating a rubber reducing 4" clay pipe (CP) to 3" cast iron (CI) coupler.

The outside diameter of the 3" CI end of the coupler fits very snug with the inside diameter of the 4" well casing (with persuasion and soap lubricant, and with the worm gear clamp obviously removed)

The inside diameter of the 4" CP end of the coupler fits very snug with the outside diameter of the 6" double pipe well seal, consisting of two steel plates sandwiching an inch thick hunk of compressible rubber in between.

The bottom steel (threaded for bolts) plate of the well seal, along with the rubber seal itself, drops into the open mouth of the CP end of the reducing coupler, and the top seal plate lands on top of the rim of the mouth of the coupler.

With the large worm gear clamp of the CP end of the coupler constraining the distention of the well seal when the four bolts are tightened, not even a flea egg can fit through a gap, much less a critter.

The resulting ensemble of funnel shaped reducing coupler and well seal even denies water from getting into the well casing.

As for the three legs, I reduced the height from the original 16" of the previously fabricated legs, down to about 12".

The old fabricated legs only had one bolt hole each to the concrete, and two of those bolts had corroded away. The bolt that remained was very solid, but a single point is a pivot point.

The new feet consisting of floor flanges with four TapCon screws each can be compared to an eagle's claws gripping a branch, versus a cow's hoof standing in a pasture. It is easier to tip a cow than it is to unseat an eagle from it's grip, even though the eagles claws are smaller than a cow's hooves.

I placed one of the pipe legs directly over the last remaining good (1/2") threaded stud in the concrete, so even if the TapCon screws fail one by one (there are 12), the pump itself cannot travel off axis away from the well, as the well pipes and seal provide one point, and the old bolt provides the other point. This is why the pump could still perform with the rusted legs.

The problem was, the tops of the rusted legs relied on 3/4 inch bolt passing through the cast feet of the pump volute base, which has holes threaded for 1/2" NPS... which is larger in diameter than a 3/4" bolt, that passes through the holes, but does not engage the threads, and, moreover, does not have an interference fit.

The holes in the mounting ears are not distanced far enough away from the pump body to utilize the flats of any given bolt head, so the previous installer ground all the flats of the bolt head off. No way to tighten the bolt, and no way to tightened the nut inside the tubes underneath.

Socket head bolts was the first idea to solve that problem, but come to find out, not even socket head bolts will clear the pump body. That's when it became clear that using the threads that already exist in the casting would be the best way to keep the pump from jiggling around in the clearance between the holes in the feet and the diameter of whatever fasteners was passing through the feet.

Six nipples were used, each 6" long, split by a union, so that that the pump could be removed without unscrewing nipples.

The pump can also be stood upright on the upper three nipples, while still clearing the MPT to barbed transition fittings threaded into the pump's adapter.

Three pipe plugs were threaded into the tops of each cast foot (illustrating the advantage of the NPS threading), to keep water out of the pipe legs.

Using the existing concrete stud as an anti-rotational "locator" pin dictated the placement of the three floor flanges, so I was able to pre plan how to make the pump more perpendicular by first using a grinder to flatten the concrete where the floor flanges would land, and then by adjusting how far the lower half pipe nipple was threaded into each floor flange.

One leg was threaded all the way in as tight as possible, until the nipple reached the bottom of the floor flange, another leg was threaded only as far in as necessary to create the friction that would keep it in place, and the third leg was threaded about half way in between the two extremes. The combination of all these actions significantly contributed to making the vertical pump stand straighter than it was before.

I changed the all the fittings to brass. I was lucky to find a brass drive pipe barb in an extended length version, so I used 4 staggered stainless steel worm gear clamps on that. The only locally available suction pipe barb in brass was of regular, so only 3 staggered worm gear clamps was used on that drop pipe.

Thanks to everyone for your input. This was my first rodeo trying to solve this type of issue. Not many in this well developed metropolitan area have wells, and the wells that do exist are for landscape irrigation only. Such is the case with this well.