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Water Well and Pump Repair/Pressure surge breaking my water valves


QUESTION: I have a 3hp Franklin Electric SubDrive 150 220v single phase residential constant pressure pump.  It maintains good pressure for house and 18 zone sprinkler, but it has two problems (1) even with large centrifugal sediment filter at the supply line, it produces substantial amounts of fine sediment which is a nuisance mostly controlled by a large floor standing self flushing sediment filter tank between supply and house &(2) water valves develop leaks through pin hole penetrations through the thick plastic of the valve at seams in the plastic.  In the past 16 months I have replaced four Rainbird electric control valves and two 1" ball valves with pin-holes that sprayed 4 feet in the air with the water pressure. One Rainbird valve was replaced with Orbit and now that one leaks.  All leaks are on the supply side and sometimes associated with a crack that formed. The pump maintains pressure but runs all the time when there is a leak.  I have noted when the water is turned on, house or yard hose, the pressure will be a little low at first and then a "bump" surge in pressure, followed by 2-3 noticeable decreasing pressure waves and then the pressure stays at the appropriate level for maybe 5 minutes until another "bump."  It makes the valves visibly "shudder," and if there is a leak it shoots the water out of the hole with much greater force for 1-2 seconds.  I don't know what the "bump" pressure is in psi, but it must be pretty high.  Could this be what is damaging the plastic valves?  Could the pump pressure sensor be bad?  Suggestions?  Thanks!

ANSWER: Yes, it could be the pressure transducer, it could be the drive itself or something else, but the holes in the valves sound like sand is eating the plastic which it will do.  A brass valve might last longer, but naturally would be more expensive.  Sand will also eat the impellers in the pump among other things in the pump.

People call everything sediment, so it makes it hard for me to know what it is that you really have.  Can you send me a picture of your hand with some of this debris in it?

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QUESTION: Picture {l) sediment in hand (2) sediment with millimeter rule (3) higher mag of same.  There is a large variation in sediment grain size.  It resembles the slurry that came out of the hole when the well hole was first drilled. I have looked up dimensions on the pump web site and have concluded there is a very small clearance between the tip of propellers and the well side casing.  I imagine the side of the well is washing away at that level of depth.  I contacted the company, and they were "ho-hum."  The person who drilled the well and installed the pump and controller will not return my calls or talk to me anymore because I keep asking what to do about the sediment.  I got a large filtration tank which keeps it out of the house without making significant bsckpressure.  When I uninstall the broken valves, they do have quite a bit of sediment accumulated inside. Tank helps to keep sediment out of the house but the plastic valves get the wear.  BTW, I kept my old well, which functioned but was too shallow and too little gpm for house plus irrigation.  It is 3/4 hp Jacuzzi set for 40-60psi cycle.  Its average pressure is much lower than the constant pressure pump.  It also produces sediment, but about 1% as much. Also, when a leak develops, it is much less if I switch to the "old" well.  I never have then on at the same time, of course.  We are using the "old" well now (constant pressure pump turned off) because a valve is leaking. Thanks.

ANSWER: That's sand mostly.  And sand is a bad thing to be getting from a well.  Had it been drilled properly, you wouldn't have any sand.  The guy that did the drilling shouldn't be in business.

The best thing for removing sand is a water softener sized tank filled about half way with sand so that the water has to go down though the sand leaving the pumped sand behind.  Then it can be back washed out when need be.  You can do this with a manual backwash or an automatic back wash like a softener head.

The best thing to do would be to fix the well/s, but it doesn't sound like that's going to happen.

I wish I could give you more encouragement, but a sandy well is always going to be a major problem.

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QUESTION: That type of sediment removing tank is exactly what I have.  The driller/pump installer kept blaming me for getting sediment because I put in paper sediment filters which he said increased the back pressure which pumped the sand.  So I got the big tank to provide greater capacity with less back pressure.  Keeps sand out of the house.  The valve in my frost-free yard hydrants also foul up and water comes out the weep hole when the faucet is flowing.  I think the sand is the culprit.  (Last question) What about this pressure surge while the water is running?  Should I change the pressure sensor?  Thank you so much - this is the most definitive answer I have found.

It could very well be the pressure sensor (transducer).  The sand might be fouling it somehow. I can't think of anything else that could cause that other than sand getting caught somewhere then letting go which could confuse the transducer making the pump spin up it's RPM's to keep up with what the controller is trying to do to maintain constant pressure.    The Subdrive can only do what the Transducer tells it to do, so that makes sense.  The Subdrive controls the RPM's of the motor by varying the frequency from 60 cycles to what it needs to speed up or slow down the pump.  This is what keeps the constant pressure.

Your contractor sounds like a a guy who makes things up as he goes.  Backpressure can't make a well pump sand.  That's the dumbest thing I've ever heard.  It just sounds like he cheaped out on casing and didn't case off the sand like he should have.  If you can get another driller to come in and add more casing, you might be able to fix the well.

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Robert Tabor


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