Deep wells: should pipe be plastic or metal? (how much, tank, insulated)
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We're having continued problems with our 925 foot well. The top section is metal but the rest of the pipe is plastic. Today is the second time they've pulled the pipe and the lower plastic section is blown out. Don't know if the pump is the problem or having a plastic pipe so just wondering what kind of pipe most folks have.
We're having continued problems with our 925 foot well. The top section is metal but the rest of the pipe is plastic. Today is the second time they've pulled the pipe and the lower plastic section is blown out. Don't know if the pump is the problem or having a plastic pipe so just wondering what kind of pipe most folks have.
5" PVC is best, IMO. Is it the plastic drop that is "blow out" or an galvanized connection?? Make sure they use BRASS, never galvanized below the ground!!! How long is the drop??? I always hang my pumps on schedule 80.
5" PVC is best, IMO. Is it the plastic drop that is "blow out" or an galvanized connection?? Make sure they use BRASS, never galvanized below the ground!!! How long is the drop??? I always hang my pumps on schedule 80.
The last section of plastic pipe has a bulge and is blown out. The very top section of pipe looks like galvanized pipe to me. What is schedule 80?
The last section of plastic pipe has a bulge and is blown out. The very top section of pipe looks like galvanized pipe to me. What is schedule 80?
Schedule 80 is white PVC. Is your drop pipe black?? If it is I am thinking it is polly. I have never seen anything happen to the plastic drop. I would replace the drop with all schedule 80. Is a driller working with you on this??
Yes it has a submersible pump, otherwise how does the pipe blow out; or how do you use jet pump in a 925' well?
Depending on the static water level and how much draw down in the well at peak demand water use and the weight of the pump, schedule 40 or 80 or PE (polyethylene) can not be used because of the pressure rating being too low and for PE the pump will too heavy. You can check the pressure rating at the link that was given.
Either excessive pressure or the pump getting hot and derating the plastic's pressure rating is causing the plastic to fail (blow out). Lucky they are losing the pump.
They are going to have problems until they go to a much higher rated material, and although I don't like galvanized, that's probably the only choice unless you go an exotic like a special hose that I saw a couple years ago if it is still available; I think it was from Australia. It looks like fire hose but it might not be rated high enough either.
Sounds like the pump is overheating for some reason. Sch 80 PVC is about twice as thick as Sch 40. It will handle more heat and pressure.
Looks like even a schedule 80 2" drop pipe would be at the hairy edge. A 925' lift puts 400 psi at the base, which is the rated working pressure of 2" in the pipe charts you provide. Add 45+ pounds for house pressure, another 15+ pounds for overcoming resistance and the height of the house above the well, and there could be problems. Heat from the pump or natural ground heat could be another factor. Downsizing to a 1" pipe would make it much stronger, but I have no idea how badly that would affect performance. Are check valves and "helper" pumps ever used on deep wells?
Looks like even a schedule 80 2" drop pipe would be at the hairy edge. A 925' lift puts 400 psi at the base, which is the rated working pressure of 2" in the pipe charts you provide. Add 45+ pounds for house pressure, another 15+ pounds for overcoming resistance and the height of the house above the well, and there could be problems. Heat from the pump or natural ground heat could be another factor. Downsizing to a 1" pipe would make it much stronger, but I have no idea how badly that would affect performance. Are check valves and "helper" pumps ever used on deep wells?
I deepest I have ever drilled is 480 ft. Then it just took 120 foot of drop. Really to get any volume of water it has to be 1" for the drop pipe. In high producing hook-ups I use 1 and 1/2". That is if I want 60 GPM or more.
I wondered if the well is pumping our of water, that is the only way I can see the pump getting that hot.
Schedule 80 is white PVC. Is your drop pipe black?? If it is I am thinking it is polly. I have never seen anything happen to the plastic drop. I would replace the drop with all schedule 80. Is a driller working with you on this??
Looks like white PVC to me. Yes, the driller's doing it. The first time the lower pipe blew out, they attached a little pressure tank to the pump. It worked for awhile then blew out again (yes, it's insulated). Now the driller, electrician (who has also tinkered with it) and the plumber are all scratching their heads. There's plenty of water down there.
Last edited by SunInHair; 01-04-2009 at 04:37 PM..
Reason: forgot to include addl. info
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