What constitutes a "properly installed CSV"?

[Kikaroo]

Forgive me if this question is unclear due to poor terminology. I'm new to pumps but am under the gun to get a new system installed. We currently have a Red Jacket "Submerga" 3 HP single phase pump sitting at 545 ft in a 560 ft well. It was installed in 1977 using a traditional installation (no CSV, no VFD) and has been running ever since. We worry it will fail soon due to its age and the fact that the tank is shot.

So I'm torn. On the one hand, I find the explanations of how a CSV works very compelling, along with the arguments for prolonged pump longevity. On the other, in discussion with a pump company that is NOT trying to sell me a VFD (they've quoted me for a traditional pump install, but have a VFD option if I want it) I'm told that they don't deal with CSVs due to reliability problems they've encountered with pump systems using a CSV. This particular company rep indicated that he encountered roughly a 20% fail rate (of the motor or some other component in the system) before he stopped installing them; but it also appears that use of a CSV does not affect the pump warranty.

For instance: the aforementioned pump dealer said that in one installation, the use of a CSV put so much pressure on PVC piping that that the pipe failed. The lesson I take from this is: use galvanized piping with a CSV. He also indicated that in his experience motors tended to fail early when used with a CSV; but he didn't know of any correlations with, say, pump or motor manufacturer. In my opinion, this particular rep seems knowledgeable: he understands the benefits of a CSV and the problems with a traditional install that it solves, but his practical experience has compelled him to avoid CSVs.

I noted also in reading up on CSVs that "a properly installed CSV" can extend the life of a pump. This all makes me think that perhaps there are certain design or install choices which can cause a CSV to play badly with a pump. Hence my question: what are they? Or conversely: what is meant by "a properly installed CSV"?

Thanks in advance to anyone who can help me sift through this mass of (sometimes conflicting) information.

 

[Texas Wellman]

Wait a minute let me get my popcorn.

 

[Sponsor]

 

[Valveman]

Sounds like they are trying to sell you a VFD. They just want you to think it is your idea. What he is saying doesn't surprise me. If he doesn't know enough to figure the backpressure of the pump and check the pressure rating of the pipe, then it is a wonder he can even spell VFD. You don't have to have galvanized pipe if your pump can't build more pressure than poly or PVC can handle. Any pump man worth his salt should be able to find the deadhead pressure of the pump, subtract the static water level, and convert to PSI to figure out how much backpressure will be on the pipe.

Then if he had any motor failures, he also doesn't know how to use a flow inducer shroud or keep the pump from being fed from the top. It doesn't take much flow to keep the motor cool, but it is important that it flows past the motor before going into the pump.

I will just say that the vast majority of people who have Cycle Stop Valves will say they have greatly increased the life of their pump. In many cases people were cycling their pumps to death every 1-3 years before adding a CSV. Now many of those same pumps have lasted 20-25 years so far, specifically because of the CSV.

Having said all that, your pump is probably not a good candidate for a CSV or a VFD. It is most likely a 10 GPM, 3HP, which can build as much as 380 PSI. You can subtract the static water level from this number, but even if the static level is say 300', that would still put 250 PSI backpressure on the CSV and well pipe. While I can make a 10 GPM, 3HP pump that builds 250 PSI work with a CSV system, it actually takes two CSV1A's to make this work. The first CSV1A sees the 250 PSI and knocks it down to 150 PSI. The second CSV1A sees 150 PSI and delivers a constant 50 PSI to the house. While this will work fine, there is not as much advantage to a CSV with a 10 GPM, 3HP pump as there is with a 3HP that delivers 20-30 GPM or more. With a 10 GPM pump, it is not hard to put in a large enough pressure tank to limit the cycling. With a 20-30 GPM pump that takes several large tanks and can still cycle the pump a lot, which is why the CSV is more beneficial the larger the GPM of the pump.

With a VFD the long wires going down the 545' to the motor is just one of the major problems. "Ringing" or the "reflective wave" created by a VFD controller causes the voltage to increase as the length of wire increases. A VFD sending 240 volts to the motor can create over 1000 volts at the bottom of the wire going into the motor because of the reflective wave problem. Harmonics, resonance frequency vibrations, and lack of motor cooling are a few of the other problems caused by VFD controllers.

Although they don't make pumps as good as they did 40 years ago, I would go back with the old traditional system. It lasted 40 years last time, so you don't have a cycling problem that a CSV or a VFD could help with.

Yours is a fairly rare circumstance. Most houses have a more normal size 1/2HP to 2 HP pump in a shallower well that can only build 100-150 PSI backpressure. On these type pumps the CSV is very useful and will greatly lengthen the life of the pump.

 

[LLigetfa]

in discussion with a pump company that is NOT trying to sell me a VFD (they've quoted me for a traditional pump install, but have a VFD option if I want it)

That is called a soft sell. Providing tidbits of truth (such as bursting poly that is not rated for the pressure) is selling FUD. Either way they get to sell you a traditional pump and want your repeat business.

 

[LLigetfa]

Speaking of pumps bursting pipes, where I bought my Grundfos, they also sell and service VFD models and they were telling me how quickly the pressure can shoot up on one that goes sideways. Poor guy nearly crapped his pants when the one he was working on blew.

I use my micronizer choked down to act like a dole valve to limit flow to keep from stirring up sediment so I was inquiring about whether I should install a PRV due to the hold-back pressure from flow limiting. I had hung the old pump on 200 PSI poly but I had shortened up the pipe due to sediment filling up the casing. After clearing out the sediment I wanted to put the new pump back down to the original depth but did not want to splice back the original chunk I cut off. I could only find 160 PSI new poly to buy.

 

[Valveman]

Burst pressure of poly and most pipe is 2 to 5 times the rated pressure.