Pitless adapters, cables, drop pipe, and check valves

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Hatsuwr

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Nothing crazy here, just an interesting pitless adapter, under-specced drop pipe, and disappointing check valve. Next and last will be the pump and motor.

Pitless Adapter

My pitless adapter is a relatively uncommon style from what I can tell. It doesn't rest on anything at the elbow. Instead, the pump hangs from a bar that sits on top of the casing. The elbow has a screw which actuates a lever to wedge it inside the casing, and in doing so compresses a seal for the discharge. The advantage of this style is that you can fit a 4" pump in 4" casing without having to deal with getting past any parts of the adapter installed on the casing.

This one is made by Wells Inc., and the style seems to be "Safety Seal Clamp-on". Can't find an exact model though.

I've wanted to try out anodizing for auto parts, and thought this bar might be a good piece to experiment on. It did not go well. It almost seems like I had the polarity reversed, but it was correct. My best guess is that it was just a poor quality casting with large segregated regions that corroded quickly. My current density and acid concentrations were pretty conservative. A few strange things I noticed during the process:

- Early on, I was having decent results and a non-conductive oxide layer had formed, but now it's just bare metal.
- I needed a much lower voltage that I expected for the current, and the voltage steadily decreased over time.
- I used aluminum foil for the cathode, expecting it to quickly deteriorate, but it seems just fine (especially in contrast to the bar.)

All said, result is pretty ugly, but it's still more than strong enough for its job. It's not like proper anodizing would have been very beneficial for it anyway.

monstrosity.jpg


The screw that actuates the lever on the elbow was stainless steel, but it has corroded quite a bit. I'm guessing chlorinated water may have entered the access pipe for the screw during well disinfection. I'll be adding a PVC plug to the top. I decided to replace the screw with a 1/2"-13 brass socket head screw. Being able to turn the screw with a wrench will help to make the seal as tight as possible without causing damage, which should be useful with an aging and apparently unreplaceable seal.

The saddle shaped seal is made of nitrile. I was able to clean and restore it fairly well with methyl salicylate, and expect it will work for quite a few more years. I initially gave it a light coat of silicone grease, but it seems especially prone to squeezing out of place so I removed most of the grease. I couldn't find replacement seals unfortunately, or even just the entire pitless adapter assembly to buy. I called the manufacturer and a couple distributors, but they had no idea what I was talking about.

screws_and_seal.jpg


Regarding the elbow itself, it's cast brass with what seems like a stainless steel pin for the lever to rotate on. Connection for the drop pipe is 1" FNPT. My main concern is the extremely rough gasket interface. In pressure testing, leaking started at the gasket-elbow interface before the gasket-casing interface. I sanded the elbow down slightly, but it still could be a lot better. Some metal-free antiseize on the screw and Fluid Film on the body will hopefully help slow down future corrosion.

I plan on prototyping a stainless steel replacement for this, but that's going to be a lot more involved than the cap from my previous post. A few initial thoughts are to:

- Model it around a standard size O-ring (maybe a 404 or similar).
- Design the wedging mechanism to distribute its load across a larger area and put more even pressure on the seal.
- Limit the wedging mechanism to the ID of the casing. (this one can exceed the ID, and potentially crack the casing)
- Give it 1.25" FNPT threads for the drop pipe connection.

pitless_elbow.jpg


Threads on the aluminum bar and the top of the elbow are 1" NPT. These parts are connected with a pipe that allows access to the tightening screw. An arrow on the right of the bar is meant to be aligned with the discharge of the elbow. Mine had a PVC pipe connecting, but it's quite old by now and misaligned, so I'm replacing it with CPVC. 1" CTS CPVC is only going to have about 75% the tensile strength of 1" Schedule 40 PVC (higher tensile strength, but smaller cross section area). I believe it will still be stronger than the PE drop pipe though, and it should retain its strength better over time than PVC.

In the picture you can see that the old connecting pipe is a bit longer than the (carefully measured) new one. I wouldn't be surprised if the hole in the casing was previously partially obstructed by the elbow.

PXL_20231013_220719035.jpg


Cable

Current cable is looking a bit rough, but should be fine until it's time to replace the pump. Total run from panel to pump is probably around 100 m (328 ft). It's twisted 12/2 gauge solid, no ground, USE or RHH/RHW, 600V. There are some damaged sections from my efforts to cut the cable from the drop pipe while still in the well. I untwisted them to do an insulation test and everything checks out except the ends, but I've got plenty of slack to work with since the pump is going to be higher up.

When it's time to replace the pump, I'll replace the section of cable in the well too. Probably with something like flat 10/2 stranded with ground, THW. 12 gauge would be fine, but it's not a big price difference and the new pump will have a higher amperage.

Only thing different I'm doing here is soldering instead of making crimped connections. Soldering vs crimping always seems to be a controversial topic in other applications, but I think it makes sense here. Soldered joints will be stronger and less resistive. One of the main benefits of crimping over soldering is vibration resistance, but the connection between the cable and the pump will be taped to the drop pipe along the entire length of the connection. I'd like to replace the joint at the top of the well with a terminal block or plug of some sort for easy connection/disconnection, but I haven't found something I'm happy with yet.

Speaking of tape though, I have some Super 33+ lying around, and that is recommended for this application fairly often. I'll go ahead and use it for now, but I'd like to find something a bit more specific for this application for the future, maybe with NSF or similar certifications. There are some chemicals of interest in Super 33+/88, probably at least partially as a result of making the tape UV resistant and flame-retardant, neither of which are needed in this application. The quantities that could potentially be dissolved in water are very low and would be extremely dilute, so it's not really much of a concern (especially after the first day or so), but it would be nice to eliminate those entirely if they don't have a relevant function.

Drop Pipe

Current drop pipe is 1" PE 3408 HDPE rated for 100 PSI. With a static water level of 130' and a cut off pressure of 60 PSI, that's a minimum of 115 PSI at the bottom. Nice work.

Will be replacing this when I replace the pump (hopefully won't need to earlier). I'm thinking the best solution here will be 1.25" PE 4710 HDPE rated for 200 PSI.

Check Valve and Barb Fittings

The old check valve was integrated into the pump, and it seems clear that it has been leaking for quite some time. When fully closed, the seal can no longer even contact the entire sealing surface. I removed it and replaced it with one from Bonomi, which I am already regretting.

They have two stainless steel models - the S800 and the S250. The S800 is rated for 800 PSI and claims "Perfect sealing both at high and low pressure." Well, I'm not sure what they consider to be high or low pressure, but mine leaked all the way from 0-90 PSI. The only other 1.25" stainless steel check valve I could get quickly was their S250. Only rated for 250 PSI and feels like it might fail if you look at it too sternly, but at least it holds a seal from 0-120 PSI (didn't test higher). It also has a higher Cv rating. I put it on top of a 4" nipple to reduce any turbulent flow it might see.

Overall very disappointed in Bonomi products, and their support was useless. The best they could do is: "We do not have any other documented cases of the same activity." Not sure if they are trying to deny that mine was leaking, or claim that it's somehow unique in doing so. They also seemed to fundamentally misunderstand how check valves work, claiming that a pressure differential greater than the cracking pressure of the valve needed to exist in order to ensure leak-free sealing. Higher pressure definitely does help with sealing (to a point), but it doesn't really have any relationship to the cracking pressure, except that higher cracking pressure would actually correlate to a decreased differential needed to fully seal (assuming all else is equal).

So... anyone able to recommend a good 1.25" FNPT x FNPT stainless steel check valve? Simmons had one I considered, but it seemed a bit crude in construction and has a fairly low Cv. Flomatic has the 80S6 VFD that seems to be quite good. I would have gone with that over the Bonomi initially, but couldn't find anyone to sell me one. Flomatic very helpfully told me that their nearby factory has them in stock and ready to ship, but that I'd have to buy from a distributor. Called a few with no luck before giving up.

For the barb fittings, I reused the existing brass ones. When I replace the pipe I'll stick with brass on the top to match the pitless adapter, but will go stainless steel on the bottom. When I bought the place, there was actually a galvanized fitting at the pitless adapter. That lasted us less than two years before corroding enough to blow a hole in its side.

PXL_20231013_234343401.jpg
 

Reach4

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Just to be clear, your question is about selecting a check valve to go right above the pump, right? I guess you know that the VFD check valves were initially designed for variable frequency drive systems, but you may have read that they have an advantage for standard pumps too.

Note that the Merrill MCK and Merrill SMCK (stainless) are similar to your pitless. I have the SMCK on a 4 inch steel casing. The advantage is that it does not reduce the diameter. This pitless feature is sometimes called thruway or clearway.
 
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Hatsuwr

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Yup, check valve for just above the pump. I'll keep using the S250 on this pump if it keeps working, but I wouldn't mind replacing it when I get the new pump. Flomatic was telling me that the primary advantage of the VFD models was for low flow velocity situations. Seems like mine fit that bill according to their metric, and there didn't seem to be any downsides except price and availability.

Thanks for the lead on the SMCK, looks almost exactly the same! Gonna send them am email now. I'm trying to plan out all the replacements I want to do when the pump eventually fails.
 

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You have way more time and patience than I do. I would replace that pitless even if I had to use a spool type. I always use a galvanized pull pipe as you don't want that to break. If 33+ tape was a problem, everyone in this country would be dead because of it by now. It is widely used in the industry. Almost any check valve will work at low flow rates. The VFD thing is just to keep it from chattering at low flow because of the pulsing effect of most VFD's. Regular Simmons or Flomatic check valves are fine. It is not the low flow that causes check valves to fail as much as the pump cycling on and off too much. I would also stay with the 1" drop pipe. The velocity in 1 1/4" pipe at low flow is not enough to lift out any sediments, which end up on top of the check valve.
 

Hatsuwr

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You have way more time and patience than I do. I would replace that pitless even if I had to use a spool type. I always use a galvanized pull pipe as you don't want that to break. If 33+ tape was a problem, everyone in this country would be dead because of it by now. It is widely used in the industry. Almost any check valve will work at low flow rates. The VFD thing is just to keep it from chattering at low flow because of the pulsing effect of most VFD's. Regular Simmons or Flomatic check valves are fine. It is not the low flow that causes check valves to fail as much as the pump cycling on and off too much. I would also stay with the 1" drop pipe. The velocity in 1 1/4" pipe at low flow is not enough to lift out any sediments, which end up on top of the check valve.
Yea the pitless adapter is a massive pain to properly align the first time, but at least it's a one time job.

That's an interesting point about having a fluid velocity sufficient to lift out sediment. I don't think there is anything large enough to be a concern in my well, but I'll inspect the check valve next time it's out before making a decision. Thanks for pointing that out.

I wonder if Flomatic will tell me any more about their design considerations. It's interesting how different the standard 80S6 is from the VFD version:

standard_vs_vfd.png
 

Reach4

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Yup, check valve for just above the pump. I'll keep using the S250 on this pump if it keeps working, but I wouldn't mind replacing it when I get the new pump. Flomatic was telling me that the primary advantage of the VFD models was for low flow velocity situations. Seems like mine fit that bill according to their metric, and there didn't seem to be any downsides except price and availability.

Thanks for the lead on the SMCK, looks almost exactly the same! Gonna send them am email now. I'm trying to plan out all the replacements I want to do when the pump eventually fails.
When I had my pit demolished, I had my StaRite Trimline pump put back into my 4-inch steel casing. If I get the pump replaced, I will go with a 3-inch Grundfos SQ pump with a flow inducer. The OD of the flow inducer will be about 3.5 inches.
 

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1. I have saw cuts at the top of my casing to mark the alignment. But that does presumed that the bar is in line with the water flow out the side.
2. For threaded PVC as a hanger, you want schedule 80-- not schedule 40. That is what they use for PVC drop pipe, except for very deep wells.
3. Why were you planning to use CPVC?
 

Hatsuwr

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1. I have saw cuts at the top of my casing to mark the alignment. But that does presumed that the bar is in line with the water flow out the side.
2. For threaded PVC as a hanger, you want schedule 80-- not schedule 40. That is what they use for PVC drop pipe, except for very deep wells.
3. Why were you planning to use CPVC?

CPVC holds up better over time compared to PVC. I'm pretty sure even 1" CTS CPVC is going to have a higher tensile strength that 1.25" PE, so my concern is more about brittle failure down the line. Schedule 80 PVC would probably be better than CTS CPVC even in regard to long term brittle failure because of all the extra material, but I couldn't get here quickly without paying an unreasonable amount, and I already had the CPVC lying around.

Is the future switch to Grundfos for the smaller diameter, or do you just prefer their pumps?
 

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Were you intending to use a pair of glued fittings to convert 1 inch cpvc to 1 inch FIP thread?


A well service company might sell you a reminant from a 20 ft stick. You would then have to thread at least one end; one end may be pre-threaded.
 
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Hatsuwr

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Yea I already made it, cemented male adapters at each end. There's a picture in the original post, below the pitless adapter. I didn't even think about cutting threads onto the pipe. Suppose it wouldn't really work with CTS sized PVC anyway. Could be funny and put 1/2" NPT threads on 3/4" CTS but I wouldn't be too happy about the remaining wall thickness.

Schedule 80 CPVC would be the best of both, but it's stupidly expensive for what it is. I'll keep an eye out in the meantime though, and if I find something will add it to the list of changes to make when pump replacement happens.
 

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Yea the pitless adapter is a massive pain to properly align the first time, but at least it's a one time job.

That's an interesting point about having a fluid velocity sufficient to lift out sediment. I don't think there is anything large enough to be a concern in my well, but I'll inspect the check valve next time it's out before making a decision. Thanks for pointing that out.

I wonder if Flomatic will tell me any more about their design considerations. It's interesting how different the standard 80S6 is from the VFD version:

View attachment 94572

If you do not have a VFD, you don't need a VFD check valve. There is a little difference in the sealing mechanism between the two valves. The seat on the VFD check valve is tapered a little more than the other. But the main difference is the shaft guide. The water swirling and pulsing from a VFD controlled pump makes the check valve spin, chatter, and not be aligned properly with each closing. The guide stem helps with that. But if you have low flow for any other reason like just throttling a full speed pump with a ball valve, Dole valve, or Cycle Stop Valve the pulsing and swirling is not a problem. But I will give it to Nick at Flomatic for filling a void. The VFD check valve is another good Band-Aid for one of the many problems associated with VFD control.
 

Reach4

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https://pvcpipesupplies.com/1-x-5-schedule-80-cpvc-pipe.html $25.32 plus shipping.

I am skeptical of CPVC being better than PVC in a well. CPVC seems to generate a lot of mistrust.
https://pvcpipesupplies.com/media/documents/physical_properties_of_pvc_cpvc_pipe.pdf has physical properties.

One thing that that table does not take into account is plasticizers. I don't know how much plasticizer PVC or CPVC pipe has. I suspect little to none for PVC drop pipe. I suspect there is some in schedule 80 PVC electrical conduit, because it seems to be a tad softer. PVC electrical conduit also has UV inhibitors. https://www.creativemechanisms.com/blog/everything-you-need-to-know-about-pvc-plastic
 
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Hatsuwr

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Minimum quantity of two and shipping brings the total to $75 haha. There's a lot of conflicting information and a whole range of opinions out there. I've had better experiences with old CPVC compared to PVC, but not to the degree that I wouldn't easily change my mind.

The little information I could find indicated that it was the greater loss of plasticizers over time in PVC that leads to its increased susceptibility to brittle failure, but I couldn't actually find any data testing this. Would be nice if someone could find some of each that had been stored together for a decade or two to test with.

For the check valves, would you say there are any downsides to the VFD versions?
 

Reach4

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For the check valves, would you say there are any downsides to the VFD versions?
I am ignorant on that, other than to observe that you have found it practically unobtainable. But no performance downside that I can predict.

A quirk that you might find interesting https://www.westlakepipe.com/sites/...119.3_CertaLok-KwikSet-ThreadedDropPipe_0.pdf page 3 shows that maximum pump depth to be greater for 1 inch PVC than for 1.25 PVC. This may be that they are calculating including the water weight, and assuming that the well could go dry. You will agree that the numbers in that top table are unexpected.

I would also observe that the SIDR adapter at the top needs to be the extra-long type using 3 clamps, with the worms staggered. You have the extra long on the bottom, but the one at the top is the one carrying the bigger load.
 
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Hatsuwr

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I am ignorant on that, other than to observe that you have found it practically unobtainable. But no performance downside that I can predict.

A quirk that you might find interesting https://www.westlakepipe.com/sites/...119.3_CertaLok-KwikSet-ThreadedDropPipe_0.pdf page 3 shows that maximum pump depth to be greater for 1 inch PVC than for 1.25 PVC. This may be that they are calculating including the water weight, and assuming that the well could go dry. You will agree that the numbers in that top table are unexpected.

I would also observe that the SIDR adapter at the top needs to be the extra-long type using 3 clamps, with the worms staggered. You have the extra long on the bottom, but the one at the top is the one carrying the bigger load.
I came across something similar when researching possible causes of the damage to my casing - smaller diameter casing can withstand more external pressure. Suppose its just a matter of the increased surface area.

Good catch on the adapter. Wasn't going to mention it since I was hitting the character limit for a post, but I'm planning on replacing the short one since it's experienced a decent amount of dezincification. The long one is fairly new, from back when I had to replace the galvanized one that was blowing itself apart. I figured it'll hold until I get around to replacing it, and that way I only have to pull the pitless out to do so and not go all the way to the pump. I was pretty impressed my the short old holding several hundred pounds when I was trying to pull the pump
 
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