“Let Me Tell Ya”: Yes, Still More on Older Submersibles
This article is going to deal with a couple of
problems that have been and, in some cases, still are inherent to the design of
many submersibles – plugged parts and underperforming check
valves.
When submersibles first became popular in my area in the early 1950s, they all had impellers that were made not much different from the impellers of jet pumps. That is, they generally were cast from brass or bronze. The outside of the impellers were machined smooth, and that was not a problem. However, the inside pathways were, as they say, “as cast,” meaning they had a pretty rough texture. This roughness was a great place for iron, calcium and other minerals to build up. With plugged impellers, the capacity of these pumps was severely limited. I, on occasion, would run plugged pumps in an acid bath for a short time, and this would restore the pump to nearly new performance.
Thankfully, manufacturers quickly became aware of this problem, and it wasn’t too many years before pumps came along that had non-metallic impellers. Each manufacturer had its own favorite material, and some of these materials were better than others, but they all allowed the impellers to be made with a much smoother inside pathway or vane, which greatly alleviated the plugging problem. Some manufacturers have gone to stainless steel impellers, which I believe are constructed of sheet stainless, and are very smooth. These also are pretty much impervious to plugging. One problem solved; here comes a second.
Just about every submersible that I ever have seen has some sort of screen or cage covering the intake portion. All the water that the pump will pump has to go through this intake. On early models, again going back to the early 1950s, the pumps I sold had intake screens made of brass or bronze with many small round holes punched into this screen. Strangely, the holes were large enough that foreign material going through them could cause serious damage to the inner workings of the pump. Why the manufacturers used these relatively fine screens is beyond me, but they must have had their reasons. At least one manufacturer – and probably more – used a screen made of stainless steel, but also with the small openings.
In the mineralized water that we have here in Michigan, it wasn’t long before we received complaints of poor pump performance. This required pulling up the pump, and we just about always found these intake screens all plugged up. With a plugged intake, no matter if the impellers were in good shape, whatever they were made of, no pump could produce its rated capacity. Our solution – Take off the screen, and throw it away. Just about all the pumps we were installing were in wells that were steel-cased top to bottom and had well screens, so there was little chance that anything very large could get into the pump mechanism proper.
In later models, many manufacturers went to a non-metallic intake screen with much larger openings. I still was mistrustful of these screens, and for many years took them off and junked them, just like I did with the metal screens. Finally, I learned to trust the factory screens, and have not had a problem with this in many, many years. Problem number two solved, but problem number three lingers.
Just about all domestic submersibles – the vast majority of what I have installed – have a built-in check valve. Now some of these will produce up to 40 gpm, which may be on the upper end of what we call a domestic pump, but I still call them domestic models. I have had all kinds of trouble with these built-in check valves. One brand, many years ago, would stick open around its guide if any sediment was pumped, and this sediment was common in older wells.
Other designs sometimes would work, and sometimes not. One manufacturer changed the design of the poppet a couple of times with mixed results. Now I am a great believer in the two check-valve system; that is, keeping the factory-supplied valve in the pump and adding a second check valve just below the pitless adaptor, which is the popular completion method in Michigan. It’s also the only one that meets code, as the service line to whatever building the well is supplying must be at system pressure at all times.
Now this two-check system has an advantage in that if the check in the pump fails, the upper check will hold the pressure in the system. Otherwise, we are going to have very rapid cycling and possibly a ruined pump. The two-check system also has a big downside. If the lower check or that in the pump has failed, when the pump comes on, after a few seconds of running, a loud thump will occur – sometimes a very, very loud thump. The thumps don’t have to occur many times before one gets a call from an unhappy customer, and the pump has got to be pulled and the lower check replaced. After a number of these type calls, I finally resorted to a plan of simply removing the built-in at the pump and installing an after-market model. This cut my service calls on this complaint by about 99 percent.
Some of my friends in the business maintain that turbulence at the top of the pump is the cause for these failures. They say that this won’t happen in a low-capacity pump. I respectfully disagree, as I have had failures in pumps pumping as little as 6 gpm and others pumping 40 gpm. Other fellows say that this all can be avoided by moving the check valve 5, 10 or 20 feet above the pump. And still others say that a single-check system – using one check valve at the pump – is the only way to go. Like everybody else, I have my own way of installing pumps, and I believe a check valve at the pump and one at or near the surface is the correct way. With the availability of good after-market checks, this is another problem that has been solved.
As I write this in mid-May, the weather seems more like early April with temps in the low 40s and at least a little bit of rain almost every day. Thankfully, we have not had flooding as our friends along the Mississippi did, but spring has been a long time getting here. We did have a couple of very warm humid days last week, and that was not much fun, either.
The best to all my readers, and next time, we’ll discuss more good, bad and indifferent features of submersible pumps.
ND
When submersibles first became popular in my area in the early 1950s, they all had impellers that were made not much different from the impellers of jet pumps. That is, they generally were cast from brass or bronze. The outside of the impellers were machined smooth, and that was not a problem. However, the inside pathways were, as they say, “as cast,” meaning they had a pretty rough texture. This roughness was a great place for iron, calcium and other minerals to build up. With plugged impellers, the capacity of these pumps was severely limited. I, on occasion, would run plugged pumps in an acid bath for a short time, and this would restore the pump to nearly new performance.
Thankfully, manufacturers quickly became aware of this problem, and it wasn’t too many years before pumps came along that had non-metallic impellers. Each manufacturer had its own favorite material, and some of these materials were better than others, but they all allowed the impellers to be made with a much smoother inside pathway or vane, which greatly alleviated the plugging problem. Some manufacturers have gone to stainless steel impellers, which I believe are constructed of sheet stainless, and are very smooth. These also are pretty much impervious to plugging. One problem solved; here comes a second.
Just about every submersible that I ever have seen has some sort of screen or cage covering the intake portion. All the water that the pump will pump has to go through this intake. On early models, again going back to the early 1950s, the pumps I sold had intake screens made of brass or bronze with many small round holes punched into this screen. Strangely, the holes were large enough that foreign material going through them could cause serious damage to the inner workings of the pump. Why the manufacturers used these relatively fine screens is beyond me, but they must have had their reasons. At least one manufacturer – and probably more – used a screen made of stainless steel, but also with the small openings.
In the mineralized water that we have here in Michigan, it wasn’t long before we received complaints of poor pump performance. This required pulling up the pump, and we just about always found these intake screens all plugged up. With a plugged intake, no matter if the impellers were in good shape, whatever they were made of, no pump could produce its rated capacity. Our solution – Take off the screen, and throw it away. Just about all the pumps we were installing were in wells that were steel-cased top to bottom and had well screens, so there was little chance that anything very large could get into the pump mechanism proper.
In later models, many manufacturers went to a non-metallic intake screen with much larger openings. I still was mistrustful of these screens, and for many years took them off and junked them, just like I did with the metal screens. Finally, I learned to trust the factory screens, and have not had a problem with this in many, many years. Problem number two solved, but problem number three lingers.
Just about all domestic submersibles – the vast majority of what I have installed – have a built-in check valve. Now some of these will produce up to 40 gpm, which may be on the upper end of what we call a domestic pump, but I still call them domestic models. I have had all kinds of trouble with these built-in check valves. One brand, many years ago, would stick open around its guide if any sediment was pumped, and this sediment was common in older wells.
Other designs sometimes would work, and sometimes not. One manufacturer changed the design of the poppet a couple of times with mixed results. Now I am a great believer in the two check-valve system; that is, keeping the factory-supplied valve in the pump and adding a second check valve just below the pitless adaptor, which is the popular completion method in Michigan. It’s also the only one that meets code, as the service line to whatever building the well is supplying must be at system pressure at all times.
Now this two-check system has an advantage in that if the check in the pump fails, the upper check will hold the pressure in the system. Otherwise, we are going to have very rapid cycling and possibly a ruined pump. The two-check system also has a big downside. If the lower check or that in the pump has failed, when the pump comes on, after a few seconds of running, a loud thump will occur – sometimes a very, very loud thump. The thumps don’t have to occur many times before one gets a call from an unhappy customer, and the pump has got to be pulled and the lower check replaced. After a number of these type calls, I finally resorted to a plan of simply removing the built-in at the pump and installing an after-market model. This cut my service calls on this complaint by about 99 percent.
Some of my friends in the business maintain that turbulence at the top of the pump is the cause for these failures. They say that this won’t happen in a low-capacity pump. I respectfully disagree, as I have had failures in pumps pumping as little as 6 gpm and others pumping 40 gpm. Other fellows say that this all can be avoided by moving the check valve 5, 10 or 20 feet above the pump. And still others say that a single-check system – using one check valve at the pump – is the only way to go. Like everybody else, I have my own way of installing pumps, and I believe a check valve at the pump and one at or near the surface is the correct way. With the availability of good after-market checks, this is another problem that has been solved.
As I write this in mid-May, the weather seems more like early April with temps in the low 40s and at least a little bit of rain almost every day. Thankfully, we have not had flooding as our friends along the Mississippi did, but spring has been a long time getting here. We did have a couple of very warm humid days last week, and that was not much fun, either.
The best to all my readers, and next time, we’ll discuss more good, bad and indifferent features of submersible pumps.
ND
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