Small subdivision shared well.

[Kyle Perkins]

Hi, My name is Kyle and I am the president of a small well users association. We have 5 households on a shared well. We have a 10hp pump system and are about 465ft down. We currently have two I believe 60 gallon pressure tanks with another that is not hooked up. This is used for irrigation also. About 1/3 acre per house. The problem is since 1999 we have been through four pumps , 4 or 5 control boxes and parts to repair, and one main box. We just had a new control box installed @ $1200.00 and are still tripping the breakers. Pump guy has checked this thing out twice and says everything is running in spec, but said we may have a winding going bad in the motor. Now we are going to have to pull the pump again and I need a direction to go so we can stop doing this every 5 or 6 years with control panels lasting a year or two. I know you are going to need details and I do not have them right now. The pump guys are pushing variable speed at us. I was thinking of a storage tank and charge pump. Or we may have to go back to the standard set up. We are not watering yet so it is just the household usage that is tripping the controller. Open to solid suggestions please. Thanks KP

 

[Valveman]

These are the kinds of systems I get thrown at me everyday. Having gone through 4-5 pumps and 4-5 control boxes in such a short time, it is obvious that the damage is being caused by cycling the pump on and off way too much. With a 40/60 pressure switch a 60 gallon pressure tank only holds about 12 gallons of water. Two of those together would hold 24 gallons and so on. But a 10 HP pump could be producing 50+ gallons per minute. I doubt the pump even has 30 seconds of run time to fill the tanks.

Simply adding a Cycle Stop Valve to the system you have will stop the destructive cycling and make the pump and controls last a long time. Adding a variable speed drive or VFD will also stop the cycling, and you have to switch the motor out to run on 3 phase power. But with the VFD you will go from replacing the pump on a regular basis to replacing the $3000-$5000 controller on a regular basis, and the VFD won't make the pump last nearly as long as a CSV.

However, we will need to know the model of the pump, how deep it is set, static water level in the well, and what pressure you are running to be able to size the right CSV for you. But once you get the CSV installed, all of those problems will go away.

 

[Sponsor]

 

[Kyle Perkins]

These are the kinds of systems I get thrown at me everyday. Having gone through 4-5 pumps and 4-5 control boxes in such a short time, it is obvious that the damage is being caused by cycling the pump on and off way too much. With a 40/60 pressure switch a 60 gallon pressure tank only holds about 12 gallons of water. Two of those together would hold 24 gallons and so on. But a 10 HP pump could be producing 50+ gallons per minute. I doubt the pump even has 30 seconds of run time to fill the tanks.

Simply adding a Cycle Stop Valve to the system you have will stop the destructive cycling and make the pump and controls last a long time. Adding a variable speed drive or VFD will also stop the cycling, and you have to switch the motor out to run on 3 phase power. But with the VFD you will go from replacing the pump on a regular basis to replacing the $3000-$5000 controller on a regular basis, and the VFD won't make the pump last nearly as long as a CSV.

However, we will need to know the model of the pump, how deep it is set, static water level in the well, and what pressure you are running to be able to size the right CSV for you. But once you get the CSV installed, all of those problems will go away.

Thanks for the quick response, You have to be a very busy guy. Question number 2: Who make the best pump motors, say for our 10hp pump? Or best pumps and motors?

 

[Valveman]

Thanks for the quick response, You have to be a very busy guy. Question number 2: Who make the best pump motors, say for our 10hp pump? Or best pumps and motors?

There is very little difference in the construction for different brands of larger pumps and motors. If it is a 4" diameter pump, you just want to make sure it doesn't have plastic impellers. Brass or Stainless Steel are the best.

It is not the design of the pump that has been your problem. No pump can survive the kind of cycling on and off you have been subjecting that pump to. Stop the destructive cycling and even the cheapest built pump will last a long time.

 

[Kyle Perkins]

There is very little difference in the construction for different brands of larger pumps and motors. If it is a 4" diameter pump, you just want to make sure it doesn't have plastic impellers. Brass or Stainless Steel are the best.

It is not the design of the pump that has been your problem. No pump can survive the kind of cycling on and off you have been subjecting that pump to. Stop the destructive cycling and even the cheapest built pump will last a long time.

I talked to the folks who have been servicing our well since they drilled it back in the nineties and here is what we have right now. A 70j10/10hp 70g pump end and a FEM61000321sf 10hp motor. I talked to them about why our new control box needed to be reset many times in a day with all of the amps readings being within spec and they told me that they had a few new control boxes that seemed to have a bad relay in them and that they would replace the relay and check things again. I spoke with them about the CSV and the first things out of his mouth were that it would burn up the pump motor for the lack of cooling flow. I have a friend who is an electrical engineer and he said that these valves have been used for many years but had the same opinion as the pump man that the motor would run hotter because it puts the pump into bypass mode? What kind of money are we talking about with this valve? Motor heat statement? I know that you are busy and this is free advice but I am confused and just want what is best for my neighbors in this subdivision. The developer of this system did a lousy job in my opinion and had I known then what I know now I would not have bought this house. Thanks KP

 

[Valveman]

I talked to the folks who have been servicing our well since they drilled it back in the nineties and here is what we have right now. A 70j10/10hp 70g pump end and a FEM61000321sf 10hp motor. I talked to them about why our new control box needed to be reset many times in a day with all of the amps readings being within spec and they told me that they had a few new control boxes that seemed to have a bad relay in them and that they would replace the relay and check things again. I spoke with them about the CSV and the first things out of his mouth were that it would burn up the pump motor for the lack of cooling flow. I have a friend who is an electrical engineer and he said that these valves have been used for many years but had the same opinion as the pump man that the motor would run hotter because it puts the pump into bypass mode? What kind of money are we talking about with this valve? Motor heat statement? I know that you are busy and this is free advice but I am confused and just want what is best for my neighbors in this subdivision. The developer of this system did a lousy job in my opinion and had I known then what I know now I would not have bought this house. Thanks KP

Well a lot of pump guys think that way. And that is how you tell the good ones from the bad ones. The good ones will know that when a CSV restricts the flow from the pump, the motor amps will decrease, the motor will actually run much cooler, and needs very little flow to stay cool. Here is a quote from an actual motor manufacturer.

"In your application (5 GPM, 7" shroud, 6" motor with an actual O.D. of 5.5") the flow velocity past the motor will be .109 feet per second. At this flow velocity at an ambient temperature of 95°F the service factor of the of the motor will be .82 and the motor must be de-rated from 10 HP to 8.2 HP with no service factor. Your application of 6 HP at 60-77°F at this same flow is well within the allowable limits of the motor rating at this reduced flow and temperature. We would expect lower internal motor temperatures, which will actually increase your service factor in this operating temperature range (60-77°F). We have performed research at temperatures above and below 77°F with "No-Flow" and the motor has performed satisfactorily. We anticipate no problem with your operating range."
http://www.cyclestopvalves.com/pumpman_6.html

The pump does not go into "bypass mode", whatever they think that is. The CSV just makes the pump think it is in a deeper well and just can't pump as much water as when it is in a shallower well. The same pump will easily pump a lot of water from a shallow well or very little water from a deep well. The pump guys have just been listening to the hype from the pump manufacturer. And the pump manufacturer will say anything he can to keep you from installing a CSV. They like to keep selling you those expensive pumps every couple of years, and with a CSV in control, the pump, motor, and controls will probably outlive all of us.

Notice the quote from the pump manufacturer says the motor will be fine with "no flow". And the CSV will never let it pump less than 5 GPM, so you are good.

You do have to make sure the system is in the parameters that will not put more pressure on the CSV than it can handle. If you are running something like 40/60 on the pressure switch, the static water level in the well will need to be at least 200' deep, to keep the differential pressure from that pump where the CSV can do its job. Since we have the pump model number the static water level in the well and the pressure switch setting is all we need to know to make sure the $650.00 CSV3B2T will work for your application.

 

[Texas Wellman]

10 HP for 5 houses? Sounds a little nuts, even with irrigation. Sounds really nuts with those small tanks.

Do yourself a favor, go out to the well and see how long it goes between cycles. Do this at a normal time of day when everybody is using water (dinner time, after work etc). I'll bet the system is cycling itself to death like valveman suggested.

Call in another company and have the system evaluated. I would also price the largest pressure tank you could find, like a 900 gallon galv. tank made by QuickTanks

http://quicktanks.com/quick_tanks_w...ks/hydropneumatic-and-galvanized-water-tanks/

Make sure you provide some kind of air maker on the system like a whitewater compressor as a water logged tank is useless. If you do decide to go with a CSV post up the results.

 

[Valveman]

As usual, TW makes some good points. But with 5 houses, and each having maybe a 10 GPM sprinkler system, it would not be uncommon to have a 70 GPM pump. The best time to check out how the pump is cycling is to watch it when about 2 of those 10 GPM irrigation systems are on. My guess is the pump will be off for about 1 minute, and on for about 20 seconds, which is why the pump and equipment is not lasting.

Since that is a 6" diameter pump, it needs a 6" diameter motor, and I would use a 7" flow inducer or pump shroud to keep the motor cool. Either that or I would make sure the pump is set above the water bearing strata and all the water flow into the well from below the motor. It is very important that the water being pumped goes up past the motor before being drawn into the pumps suction.

And please let us know how much a 900 gallon hydro tank and a Whitewater compressor cost. And then understand that a 900 gallon pressure tank will only hold about 100 gallon of usable water. So a 70 GPM pump is still only going to get about 1.5 minutes of run time, which is still not enough for a pump like that.

And yes it is nuts to have such small tanks on that system. I would not be taking advice from the person who set up a system like that. And they are trying to tell you that a CSV will burn up the pump??? It is certain that they have no idea what burns up pumps or what makes them last longer.

 

[Craigpump]

Sounds to me as though the system was designed for planned obsolescence and until now no one questioned the design.

 

[Texas Wellman]

Aw come on now valveman. 900 gallon H.P. tank does in fact have a 100 gallon drawdown (91.8 at 30-50). But, with a pre-charge, it bumps it up to 278 gallons at 30-50 and 241 gallons at 40-60 psig.

List price on that tank is about $6500 and probably throw in another grand for the WW compressor. Add in installation etc. and you're getting close to $10K. Which sounds like a lot, but I'm willing to bet that each time that pump fails it's costing $5-8K to swap (haven't priced one of those in a long time LOL). So I'd say that spending 10K once to $5-8K every 5 years works out much nicer. Now I know you're going to say that if they had a CSV it would cost much less and still work but the first time the power goes out nobody would be able to even flush a toilet. With that big tank you could get out several hundred gallons of water (or more) and get by for several hours and still have water. I might even say that you could do the tank and CSV and it would work.

 

[Valveman]

Aw come on now valveman. 900 gallon H.P. tank does in fact have a 100 gallon drawdown (91.8 at 30-50). But, with a pre-charge, it bumps it up to 278 gallons at 30-50 and 241 gallons at 40-60 psig.

List price on that tank is about $6500 and probably throw in another grand for the WW compressor. Add in installation etc. and you're getting close to $10K. Which sounds like a lot, but I'm willing to bet that each time that pump fails it's costing $5-8K to swap (haven't priced one of those in a long time LOL). So I'd say that spending 10K once to $5-8K every 5 years works out much nicer. Now I know you're going to say that if they had a CSV it would cost much less and still work but the first time the power goes out nobody would be able to even flush a toilet. With that big tank you could get out several hundred gallons of water (or more) and get by for several hours and still have water. I might even say that you could do the tank and CSV and it would work.

OK with the pre-charge from a Whitewater compressor you get 240 gallons instead of the usual 100 gallons of drawdown. That would be a little over 3 minutes of pump run time, which is much better than what he has now. But with a 35 GPM irrigation demand that is still 6 minutes on and 6 minutes off. Worst case scenario that can still add up to 120 cycles per day for a pump that can survive a maximum of 100 cycles per day.

And as far as water storage during a power outage, it still depends on the pressure in the system at the time the power shuts off. With a 30/50 switch, if the power shuts off when the pressure is at 31 PSI, you would only have a few gallons in the pressure tank. Taking a chance that a pressure tank has any water stored for power outages is a crap shoot at best. And if the power is out for more than a few minutes, a generator is the only way to have any water flow.

However, a big pressure tank like that would be my second choice. There is a big difference between $10K for the big tank or $650 for a CSV. And with the worst case scenario as mentioned above, the big tank would still cause 120 cycles per day while the CSV would only allow 1 cycle.

Compressors can also be just another opportunity for a failure. Here is a picture of a 10,000 gallon tank after the compressor failed to shut off. The end of the tank blew off, hit the power lines, and knocked the city out of power. The tank blew off the stands and it was just lucky it happened in the middle of the night when no one was around to get hurt.

 

[Texas Wellman]

Ah but if you have your 35 gallons per minute of irrigation and you have a 70 gpm pump you are only filling the tank at 35 gpm not 70. So instead of a 3 minute run-time you stretch it out to 6-8 minutes, depending on needs. Which is still only about 1/2 of what they need. And if anybody in the 5 houses is using water for anything other than irrigation (which they will) you then are drawing 40-50 gallons per minute and only filling the tank at 25 gallons per minute, giving you Closer to ten minutes of run time cycles. Which is still short (Franklin says 15 minutes between starts). So then you spend $650 for the CSV and have a big tank and then have the best of both worlds, which is what I would do if it were my job.

And Cary do you really think you only have a "few gallons left in the tank" at 30 psig? You can draw water out of a H.P. tank until the pressure reads "0" of the air reaches the outlet line, and if you're smart you'll put the outlet line on the very bottom.

The picture above was the result of either a failed PRV or not having one installed. My money is on the latter.

 

[Texas Wellman]

Oh and no matter what the OP decides to do (bigger tank, CSV, combination of both) you need to do something. I suspect that your current pump is already bad and the installers know it and they are limping it along. Pump #5 is coming up quickly and if I were you I would talk to 3-4 different companies and get detailed information and find out from each one why the pumps are failing so quickly. Per Franklin Electric that motor requires 15 minutes between starts to cool off. Anything proposed that doesn't increase the cycle time is a losing proposition no matter if you go with a larger tank and a CSV. A CSV would definitely be the cheapest fix and would probably do the job. I would stay away from VFD's.

 

[Valveman]

Ah but if you have your 35 gallons per minute of irrigation and you have a 70 gpm pump you are only filling the tank at 35 gpm not 70. So instead of a 3 minute run-time you stretch it out to 6-8 minutes, depending on needs. Which is still only about 1/2 of what they need. And if anybody in the 5 houses is using water for anything other than irrigation (which they will) you then are drawing 40-50 gallons per minute and only filling the tank at 25 gallons per minute, giving you Closer to ten minutes of run time cycles. Which is still short (Franklin says 15 minutes between starts). So then you spend $650 for the CSV and have a big tank and then have the best of both worlds, which is what I would do if it were my job.

I agree with you completely. But remember when the demand is more like 50-60 GPM and the run time increases from 3 minutes to to 10 minutes, the off time decreases as well, which doesn't change the 15 minutes between starts. And that 15 minute thing is the maximum it can tolerate, less cycling is always better. But with 5 houses and that large of a pump, even with a CSV I wouldn't use a really small pressure tank either. Just not nearly as large as I would without the CSV. Any time you are using more than 5 GPM the CSV is making the amount the pump can produce exactly match the amount being used. The pump will run continuously and the water goes right past the tank. It would not matter if it were a 1 gallon tank or a million gallon tank.

The CSV is only going to be using the tank when the demand is less than about 5 GPM. Then the CSV works like a 5 GPM pump as far as the tank is concerned. If you are using 3 GPM, the other 2 GPM goes into the tank until it is full. If you are using 1 GPM, the other 4 gallons goes into the tank until it is full. Then you have the full draw down of whatever size tank you have to use before the pump is restarted. So instead of a 900 gallon tank, you can use an 80 gallon tank (or two 60's as they are in service now) and still get the same 15 minutes between starts as required. The difference is with the CSV the 15 minute between starts thing only happens with the worst case scenario of using less than 5 GPM. When using more than 5 GPM there is absolutely no cycling with the CSV. Yet the 900 gallon tank without a CSV would cycle the pump for any and every flow rate.

And Cary do you really think you only have a "few gallons left in the tank" at 30 psig? You can draw water out of a H.P. tank until the pressure reads "0" of the air reaches the outlet line, and if you're smart you'll put the outlet line on the very bottom.

"Until air reaches the outlet line" is the key. You would actually get more water after a power failure without pre-charging the 900 gallon tank. Yes you would only get 90 gallons of draw down between 50 and 30, but as you said quite a few more gallons of water will still be coming out, even though the pressure drops all the way down to zero or nothing. But if the water is just above the outlet line when the tank is pre-charged to 28 PSI, you will only get a few more gallons until at 28 PSI, the air starts blowing down the pipe line to the houses. Without pre-charging the tank, if the power goes off, you might get 200 gallons to dribble out the faucets until it completely stops. Pre-charging will get you 240 gallons of draw down, but probably only about 20-30 gallons after the power goes off.

The picture above was the result of either a failed PRV or not having one installed. My money is on the latter.

Sure the PRV failed. But the PRV was only needed because the pressure switch, and/or probe, and/or relay, and/or compressor failed first. Just several more possibilities for failure, and apparently more than one of them failed to cause that kind of problem.

 

[Ballvalve]

The problem is the imbecile that sold them on a 10 hp pump. WRONG. This is not an industrial park with a cannery. At most, I would give them 1 HP per house. And what sort of houses are these? Big McMansions with 5 baths, pools and 12 foster kids in each one? Very doubtful. With a mix of uses and a csv, I would venture 3hp, especially with that giant tank. I have 2 rental houses on a 1/2 hp pump for 12 years, about 10 persons total, and never a complaint. If I was starting that clusterf##k again, I would have a 1 hp pump in the well, a 5,000+ gallon cistern, and a 5 hp booster pump on the surface. The stupidity of the pump meisters in this country is astounding. It is only exceeded by greed in this drought area.

As to that blown tank, I see rivets, so I see granpa's handi work. The PRV was just the rotten end of that antique. I am sure the compressor, tank and piping would have had prv's and weak points to blow first. In that case the weakest link was the tank cap. I always point my big compressors so the ends taking a ride in space won't hit the toilet or office. I have one pressure tank that is dated 1932 - it has, incredibly, BRASS ends, brazed to the steel shell of the tank. That was one good builder!

 

[Valveman]

The problem is the imbecile that sold them on a 10 hp pump. WRONG. This is not an industrial park with a cannery. At most, I would give them 1 HP per house. And what sort of houses are these? Big McMansions with 5 baths, pools and 12 foster kids in each one? Very doubtful. With a mix of uses and a csv, I would venture 3hp, especially with that giant tank. I have 2 rental houses on a 1/2 hp pump for 12 years, about 10 persons total, and never a complaint. If I was starting that clusterf##k again, I would have a 1 hp pump in the well, a 5,000+ gallon cistern, and a 5 hp booster pump on the surface. The stupidity of the pump meisters in this country is astounding. It is only exceeded by greed in this drought area.

As to that blown tank, I see rivets, so I see granpa's handi work. The PRV was just the rotten end of that antique. I am sure the compressor, tank and piping would have had prv's and weak points to blow first. In that case the weakest link was the tank cap. I always point my big compressors so the ends taking a ride in space won't hit the toilet or office. I have one pressure tank that is dated 1932 - it has, incredibly, BRASS ends, brazed to the steel shell of the tank. That was one good builder!

You got to remember the well is 465' deep. Where a 10HP will produce 70 GPM a 1HP would only produce 7 GPM. But with a cistern storage tank 7 GPM would go a long way and probably be all they would need. I just don't like having to go to a cistern unless I have to. The water is no longer fresh from the well and will also need chlorine added to keep nasty things from growing in the cistern, since it is exposed to air. Then you have to pump the same water twice, so you have twice as much equipment to maintain.

There is no reason this system cannot work directly from the well. It has just been cycling to death. So I would have never set up a system like this without a huge pressure tank or a CSV. And I would certainly not be considering a VFD system from a company who doesn't even know enough to make a pressure tank system work properly.

 

[Texas Wellman]

What he said. I would like to know the pumping level but 5 hp would probably do the trick.