[untilthird]

HI, I put a new pump in my well in Dec.2007, so far it has busted the drop pipe THREE TIMES :mad: Can't figure it out. I know its something to do with pressure, but what, when I cut the old busted piece off, and reinstall the pump it usually lasts 4-5 days and does it again, I have close to 300 ft, can any one help. Thanks Gary. :confused:

[hkstroud]

What kind of pipe and what pressure do you have at the well tank?

[untilthird]

The black plastic pipe and I have around 50 psi.

[hkstroud]

Is this flexible well drop pipe, polybutylene, or ABS?

[untilthird]

Not sure, I think it is polybutylene. Some one told me that I need to use shed. 80 pvc pipe.
Going to try and go with that.

[speedball1]

the black plastic pipe and I have around 50 psi.

Just got to be thin wall pipe that's blowing out. I think going to Schedule 80 PVC is overkill. Schedule 40 should do just fine with 50 PSI. Good luck, Tom

[albinfla]

I think you are on track with the schedule 80 pvc. Especially at 300 feet of depth! Most of the well guys here in our area use schedule 80 pvc, with threaded ends, and threaded couplings so they don't have to wait on glue to dry. Glue will tend to slip out with the weight, unless you really let it set up a long time.

For what it's worth, your poly pipe is probably stretching due to the depth and weight.

If you can't find threaded schedule 80, you could get plain schedule 80, and glue threaded fittings at least a day before. Then you can use threaded couplings when you reinstall. Oh yeah, only use pipe joint compound on the threads. Not tape. Tape will tend to expand the female threads and make them crack over time.

Another option is to use heavy polyethylene pipe. If you use 160 psi rated poly, it should be heavy enough to hold up. However, I have never used it in your application. Just this week, I ran a 500 foot 1" supply line from a well to a warehouse. That was pressure rated poly. Make sure you use the right fittings on the ends if you go that route.

If I were doing it, I would still go Schedule 80. A word of caution though, it will get heavy at that depth.
Al

[EPMiller]

Schedule 40? Schedule 80? Where we are, we use poly pipe down 400 ft or more. I don't think I've seen threaded pipe on a residential well since we pulled the jet pump lines (1.25" and 1.5" steel, 200+ ft) when I was a kid on the farm! I've never seen glued pipe.

You MUST have torque arrestors on the pipe or the movement from the pump starting and stopping will break things pretty fast. If I recall correctly, (haven't done a well in more than 5 years) I put a torque arrestor on every 40 or 50 feet. They are a plastic disk that keeps the pipe approximately centered in the well. They also help keep the pump wiring and safety rope neat and safe from abrasion.

[albinfla]

Very different here in FL. Nearly nobody uses poly down the well. I've been in the water treatment business almost 20 years, and the only wells with poly-pipe I've even seen are on deep well jets... Interesting!

[jlisenbe]

Until, you need to keep one thing in mind. You might have 50# of tank pressure, but just the three hundred feet of wellpipe puts about 125# of head pressure on the pump in addition to the 50# of tank pressure. Factor in the torque from the pump cutting on that EP mentioned, and you might be asking a little too much from your pipe. I think Al is on track about the threaded sched 80 pipe. One thing for sure... what you are using is not working.

[EPMiller]

Until, you need to keep one thing in mind. You might have 50# of tank pressure, but just the three hundred feet of wellpipe puts about 125# of head pressure on the pump in addition to the 50# of tank pressure. Factor in the torque from the pump cutting on that EP mentioned, and you might be asking a little too much from your pipe. I think Al is on track about the threaded sched 80 pipe. One thing for sure...what you are using is not working.

The only extra pressure on the pump is the depth to the water level in the well. The last 2 wells I worked on were less than 20 feet down to the water level which only added 10 psi to the 50 in the tank. The pump torque is what I would worry about most. If I recall correctly that poly tube has a rating somewhere north of 150 psi. However if it is stressed improperly on installation, or there are no torque arrestors, all bets are off on how it will hold up.

EPM

[jlisenbe]

With due respect, EP, I don't think that's correct. With the system in operation, there is around three hundred feet of water in the wellpipe above the pump. Any way you cut it, at a little more than 0.4# of pressure per foot, that is about 125# of pressure. Throw in the fifty pounds of tank pressure, and that is above your stated limit of 150# or so of pressure. With pump torque thrown in for good measure, it is plainly obvious that his wellpipe is not up to the job.

[EPMiller]

With due respect, EP, I don't think that's correct. With the system in operation, there is around three hundred feet of water in the wellpipe above the pump. Any way you cut it, at a little more than 0.4# of pressure per foot, that is about 125# of pressure.<snip>

jlisenbe, No, I stick to what I said. It's simple physics. The pressure of the water in the pipe BELOW the level of the water in the well does not add to the working pressure seen by the well pipe.

Lets take the pressure tank out of the equation. Let's assume a water table of 20 feet below the open end of the pipe, which would be 0 psig at that point. Each foot of vertical drop causes the pressure increases by 0.4 psig, so at the water table we have 8 psig of pressure. From there on down the water pressure inside the pipe (pushing out) is balanced by the pressure of the water outside the pipe (pushing in) so the total pressure (pushing out) on the pipe is only what is applied by the head above the water table. Now you add the pressure tank at 50 psig and you come out less than 60 psig working load.

The pipe itself will easily be up to the job. His problem is any one or more of the following; improper or missing torque control, improper fastening at joints, pipe damaged on install, or just plain bad install which would include misaligned fittings, bending around obstructions with corresponding stress points, overheating to expand over a barb, wrong fittings, on and on. It is difficult to tell without more detail.

EPM

[jlisenbe]

Are you suggesting that this man's submerged pump put three hundred feet down would have 280 feet of water above it? Sorry, but I'm not going to buy that. I can't imagine anyone drilling down three hundred feet when the water table is only twenty feet down. You are correct that the depth below the water table would not factor into any additional pressure, but to suggest that the great part of the well is filled with water?? Maybe things are done differently where you are, but I can't imagine that being the case here.

You might be correct about the ability of the pipe he is using to handle the working pressure of the well, but I can't imagine any well done the way you seem to be describing it.

[EPMiller]

Are you suggesting that this man's submerged pump put three hundred feet down would have 280 feet of water above it? Sorry, but I'm not going to buy that. I can't imagine anyone drilling down three hundred feet when the water table is only twenty feet down. You are correct that the depth below the water table would not factor into any additional pressure, but to suggest that the great part of the well is filled with water??? Maybe things are done differently where you are, but I can't imagine that being the case here.

You might be correct about the ability of the pipe he is using to handle the working pressure of the well, but I can't imagine any well done the way you seem to be describing it.

jlisenbe, I can only speak to what I experience where I work. Many local residential wells supply 5 or less gallons per minute. Some as little as 0.5 gpm, below that it is called a seep well. We are in limestone, so we have to drill down until we hit a 'stream' that will supply enough for the demand. Usually that is below 200 ft, but then the water will come up to within 20 to 40 or so feet of the surface. It is called reservoir, and without it, the well is almost useless for modern demands. There are plenty of wells around here that are 600 feet (or even more) deep because they need that reservoir, they just didn't get any good flow. Evidently you have to drill way down to even get to the water table. I then fully agree that you might need heavier well pipe, because it would be in the dry part of the hole and would not get the benefit of the water to help control both the torque and pressure.

I have a feeling we are discussing this from completely different perspectives. Very interesting. How deep are wells in your area and how deep is the water table? What are you drilling through? How deep do you have to case the wells? We often only have to case 40 feet and that is 30 feet into solid rock. The farm I grew up on has about 3 to 4 feet of soil and then it is solid limestone to who knows where.

EPM

[jlisenbe]

You are correct... different perspectives. Here a well can be anywhere from one hundred to three hundred. Water associations will go five or six hundred feet, perhaps a little more. But when we hit water, the water table will generally sit towards the bottom of the well instead of rising up the well shaft. We are going through clay and sandstone/shale here. I see your point after what you described. Interesting discussion.

[EPMiller]

Yes, I am glad it went as far as it did. I learned something about how others live and work. Thanks.

[albinfla]

Interesting exchange of info. Here in central FL, often the deep wells are artesian in the rainy season. IE, if they drill a well over 400', there are times that the water will flow out of the top of the well without a pump. I have treatment equipment on several of those wells in the area. You have to really get the seal sealed good, or it will push water out around the drop pipe, or sometimes around the conduit. I've even had to drill holes in the bottom of conduit to keep the water from running up into the controls. Interestingly enough, shallower wells of say 50-100 feet are almost never artesian, even if their static water level is only 10' deep.
Al

[jlisenbe]

We live on an interesting planet.

[dmrandyman]

I have talked to several well drillers in my area, they warned me not to use poly drop pipe further than 150 feet. I chose to use pvc pipe schedule 120 otherwise galvanized was my next choice. You did not say what type of pipe you used. My well is 300 feet with a static of 100 feet. Also what type of break have you had did the pipe snap or burst.