residential submersible pump 1

[danw2]

A precipitous drop in the house water pressure sent me to check the pressure on the bladder tank - only 20 psi on system with a pressure switch set for 30-50 psi. I clamped an ammeter on one of the pump wires at the breaker and its running continuously @ 7A, like it should since it hasn't reached cut-out at 50 psid, but it's not producing any pressure greater than 20psi with no load on the system.

I turned the 240V pump breaker off and the water pressure dropped to zero over 3-5 minutes, so the water's draining back through the pump.

Clearly the 30+ year old submersible well pump is on its last legs.

My question: Any opinions about US residential submersible pumps? Brands to use or brands not to use?
Given the costs of replacing, I'm not looking for cheap. I'm looking for quality that'll last and I'm willing to pay a premium for a better product.

Dan

 

[Artisi]

Google Grundfos and look for your local supplier. Probably the best unit round today, they can also supply bladder tanks and upto-date control systems for constant pressure operation.

 

[thewellguy]

The major brands on the market in my area are sta-rite, goulds, and grundfos. Each of then have different product levels. I would would recomend one that has stainless end bells not plastic.

The situation that you discribed could also be a hole in the pipe between the well and the house, however based on the age I think a hole is the pipe in the well is likely.

You also may want to consider going with a constant pressure system (VFD) Both Goulds and Grundfos (I prefer Grundfos) have this systems on the market. We have installed many of them and have had good reports. Mostly people like the fact that there is only a small tank and that the pressure doesn't flucuate.

 

[Valvecrazy]

Thewellguy, what is the oldest Grundfos SQE you have running? Even though they spin at 10,000+ RPM instead of the standard 3450 RPM, I agree that they are probably the best of the VFD pump systems available for domestic use. However, there is no way he or anyone else will get 30 years out of one of these VFD systems. That is exactly why the pump companies are promoting these type systems. If they average over 5 or 8 years of life, I would be very surprised and the pump companies will quickly redesign them to shorten the life.

A recent customer of mine had several problems with a Grundfos SQE. In the 4 years of service he had several problems and finally had to replace the $500.00 controller. He expressed his unhappiness with the short life and problems he had to Grundfos. Their response is that his system had already lasted 4 years, as though he should be happy with that.

There are no pumps built like the ones that were produced 30 years ago. Planned obsolescence has become a major design criteria for pump and motor manufacturers in the last couple of decades. If you want something to last, use a standard 4", 3450 RPM pump and motor, in any of the above brands listed, with a "constant pressure valve" and a 20 gallon size tank. This type system has already proven to at least triple the 7 year average life expectancy of a pump system. It will deliver "constant pressure" performance better than the variable speed pumps, without the added expense, short life, and side effects created with the variable speed pumps.

See this Link;

http://www.powerqualityanddrives.com/payback_analysis_vfd/

 

[thewellguy]

Hi Valvecrazy,

Where you at the Il water well show last week? I was going to stop by your booth but ran out of time.

To answer you question, the oldest one I have installed is about 5 years. And to ask a question of my own, what is the oldest cycle stop valve in continuous operation?

I appoligise for not mentioning you product, I should have known you would call me on it. Danw2 the cycle stop valve is also valid alturnitive to a standard system.

If you go with standard system, make sure that the air pressure in the tank, when the system is off and drained down is 2 psi less that the turn on pressure of the switch.
for example, tank 38 psi switch on at 40 psi off at 60 psi.

 

[Valvecrazy]

Thanks thewellguy!
Some of my guys were in Il, but I rarely get to go to shows anymore.

Started installing these valves in 1993. As far as I know, all of those first valves are still working. We have had a few valve failures caused by excessive sand damage or freezing. Even with those, we have less than ½ of 1% of valves returned. And of these few, rarely is there an actual problem with the valve other than an occasional pin hole in the casting caused from having to use a low lead allow. There has never been a pump or motor failure associated with our valves. I can say that these valves triple or better the life of a pump system because of the accelerated test cases. We put these valves in house systems with Drip irrigation and heat pumps, where previously the pump would only last 2 or 3 years. The first one quit after 12 years and the others are still running. Even the pump that quit after 12 years lasted 4 times as long with the valve as without. Also changed out 80 gallon pressure tanks for 20 gallon tanks just to accelerate the tests further.

Seems to be the biggest problem in selling these valves. Since they make pumps last longer and use smaller pressure tanks, all pump manufacturers and even some installers don't like it. Most pump installers however, still try to make systems last as long as possible. Many installers don't even realize that they are being sold pumps that were designed with shorter life expectancies. They just don't understand why pumps don't last like they used too. Installers have had to get better at installations, because pump companies keep giving them shorter motors and cheaper built pumps.

Nearly all pump companies are now pushing Variable Speed Pumps. Do you think they are doing this to make pumps last longer and be less expensive to the end user? I don't think so!!

 

[RossABQ]

Personal opinion, even for a single family residence, the extra cost of a storage tank (say 3,000 gallon) with a separate pressure pump and AmTrol type bladder, is the premium setup. This way the well pump comes on infrequently, but runs a long time when it does. Obviously its pumping rate can be lower since it doesn't have to match peak consumption rate. I put in a system like this on a 1050'-deep well and it was better than any city system for steady pressure, no surprises in the shower. The cost of the tank and extra pump was about $2500 in 1988.

The biggest problem with it was voltage spikes from lightning hitting the overhead power lines in the neighborhood. Took out two pumps in 5 yrs. Having 3,000 gallons gives you some time to get the well pump fixed when this happens.

 

[danw2]

Thanks for input.

I pulled the pump this morning and there were two sources of leaks. The main pressure leak came from a galvanic corroded leak on the junction of a galvanized pipe nipple on the outlet of the pump and a brass check valve above it: a good sized hole.

However, piping above the check valve held water. The pressure bleed down when I turned power to the pump off was due to leaking O-rings on the pitless adapter, which for you Suthrun boys, is an adapter that gets the water out of the well casing and into the pipe running to the hosue which is buried below the frost line.

Surprise, the pipe in the well was sch 20 PVC (done 33 years ago).

My wife and chilluns like having their showers, dish washer and toilets back in normal mode.

Dan

 

[VAMechE]

Valvecrazy,

Are you saying that all VFD drives have a lifetime of 5 to 8 years? I just designed a water treatment system at work using 2 Grundfos 5 hp pumps. These have integrated VFD drives and I would hope we get more than 5 years out of each one.

 

[Valvecrazy]

Every time you purchase a VFD, you are a Genie Pig. Even if you know of a particular Drive that has lasted 5 years, they no longer make that model. Every 18 to 24 months a new chip comes out that replaces the old chip. So new Drives come out to replace the "old" Drives. Even parts are usually no longer available. I know there are some companies who guarantee to keep old parts available for at least 10 years. However, most people who replace parts in a Drive, usually end up wishing they had just replaced the Drive instead.

If you are using the Grundfos centrifugal pumps, such as the C series, they have a little longer track record so, 5 years may be a close guess. If you are using Grundfos submersibles, the 5 HP VFD system has not been out very long, so nobody knows how long they will last. The smaller Grundfos submersibles with VFD are the SQE models. These are probably one of the best VFD systems available for small submersibles. I have heard of some of the SQE pumps still working after 8 years. However, the average life is much less than that. They have also made numerous and regular changes to this system, so it still must not be quite right. Even one of my customers was told that he should not be unhappy about having to replace an SQE controller, because after all, the system had already lasted 4 years.

I have a good friend who has been working with Drives everyday for over 20 years. His experience shows that the average life of smaller Drives is only 3 to 4 years. Larger Drives may last 10 years or longer by virtue of a few repairs so, 5 years is probably a good average. Personally I think 5 years is optimistic, as I have replaced many Drives that were only in service for a year or two.

Of course I am saying this in a forum that is full of VFD experts. Many people make their living mitigating the numerous problems of Drive controls. I am sure I will not get the last word on this. You should consider the source of the information. If they make their living working on or selling Drives, their input on this subject as well as energy consumption, will probably be overly optimistic.

That being said, I installed many Grundfos pumps as far back as 1974. Without having Drives for controls, many of these pumps are still in service without any repairs to date. Grundfos makes good pumps but, I think I can say with confidence that a Drive or the pump it controls, would never last as long. It has been my experience that a Drive rarely saves enough energy to ever pay for itself. The shorter the life of the Drive, the more negative the pay-out becomes.

 

[FACS]

Replace the drop pipe
Replace the pump
Think about a new tank

Forget the rest.


Charlie

http://www.facsco.com

 

[Valvecrazy]

I agree with you FACS, and I believe the OP has already done that and taken care of his problem. VAMechE probably should have started a new thread with his question. I believe it is a very good question, and maybe the Mods will agree that it deserves a thread of it's own.

 

[VAMechE]

Valvecrazy,

The pumps in question are a CRIE 15-2. The reason I went with them is that my boss seems to think the 10 states says you can't use a back pressure regulator (because of a restriction on having cross connections). When I read the reg I didn't interpret it that way, but he is the boss, so I used a VFD drive and will program it for constant pressure. I'm pushing well water through a 1 absolute micron filter, and it can have as much as 30psi difference across the filter. So as the filter clogs the pump will ramp the pressure up to keep the outlet of the filter at a constant pressure. I am really hoping we are not replacing a drive/motor every couple years! We have other grundfos pumps that are going on 8 years old with no problems other than seal leakage.

 

[Valvecrazy]

I don't understand what back pressure valves would have to do with cross connections? I would have put a pressure reducing type valve after the filter and set it to maintain a constant pressure. Even if those pumps last 10 years, that is only ½ or 1/3 of the life they should give. The seal leakage is probably caused by vibration from resonance frequencies at critical speeds. When the seal leaks, it sprays water up in the motor, then the motor needs fixing.

Attached is a picture of some of those C series pumps that I installed with Drives in 1992. The problems we had were constant, and mainly with the Drive itself. However, we also kept having bearing damage from rotor currents, vibration and seal problems, and winding failures. The drives have been replaced several times, and the system still runs on bypass most of the time with valves controlling the pressure.

 

[Valvecrazy]

Trying that picture again in PDF.

 

[VAMechE]

I take it those are the drives on the wall? These new C series pumps have the drives built into the motor. Not sure if that is a bad thing after reading your posts! I'm now considering redesigning the system to use a pressure regulator, but I would have to get some documentation from the BOH saying it was OK to show to my boss.

 

[Valvecrazy]

Putting the Drive on top of the motor shortens the wire length between the Drive and motor. This reduces the voltage spikes to the motor somewhat. In this way they are also able to use the motor fan to cool the Drive. Unless you keep it in a perfectly clean environment, this larger fan will draw in extra lint, dust, and bugs. A Drive on the motor also has to endure the vibration as the motor continually goes through it's critical speeds. If we allow manufacturers to do it, soon all pump motors will have a Drive incorporated into the design. In this way, on the incorrect pretense of saving energy and keeping the polar ice caps from melting, pump and motor companies can count on getting to sell you a new system much sooner. Getting you to purchase equipment on a regular and timely basis is the primary goal of most corporations. The fact that you must pay a premium price because it has a Drive incorporated is a bonus, as well as being what keeps the replacement cycle shorter.

Motor companies have had to change from 600 volt insulation to 2,000 volt insulation as standard, to better withstand the voltage spikes and rapid rate of voltage rise caused by Drive controls. Many are making insulated bearings or grounding the rotor to limit bearing damage from Drive controls. Some even incorporate an additional squirrel cage fan to increase the cooling air flow to the motor when at low speeds. Motors being beefed up in this way is the only reason they can survive the normal abuses from a Drive. They still will not last as long as motors running on standard AC power. I guess the question is, how long do Drives really last?

This link;

http://www.powerqualityanddrives.com/payback_analysis_vfd/

talks about the life of a Drive being 8 years from their experience. This analysis shows the first Drive as being GIVEN to the user for free. In 8 years when the Drive fails, the end user must purchase the second Drive themselves. This shows a negative payout as soon as the end user spends money on a Drive. I submit that if you have to purchase the first Drive yourself, payout becomes negative immediately.

My experience has shown that a Drive lasting an average of even 5 years is overly optimistic. 5 years or 8, either way in most pump applications, the Drive will not last long enough to pay for itself. Especially because the difference between power consumption of a Drive verses a Valve is very slight in most cases.

The C series pumps controlled by Drives in the picture I attached were installed in 1992. These motors have been rewound, and the bearings and seals have been replaced several times. To my knowledge the Drives have only been replaced twice in this time period, which totals 3 Drives in 16 years. These pumps use almost exactly the same amount of power when running with the Drives as they do when controlled by Valves. So the Drives give no energy savings to justify the added maintenance and replacement cost.

There is nothing more dependable, long lasting, and efficient than a squirrel cage induction motor, running on standard AC power using across the line controls, and spinning a centrifugal impeller. I can personally show you some of these type pumps that have lasted 30+ years working this way. It is also very common to find 30 or 40 year old pressure reducing valves that are still working fine. In my opinion it is the energy used to mine, manufacture, transport, install, and maintain short lived Drives and motors that is melting our polar ice caps, and increasing your operating expense. Not to mention down time and head aches.