Is larger pipe size a problem with a well?

[Odysseus99]

I have a 400 foot deep well, have not yet put in a pump. Water at 300 ft., 6" steel casing. I was planning to use 1" drop pipe for the pump up to the pitless. Recently I found a good deal on 1-1/2" stainless steel schedule 40. Question is- is there any problem with using a larger pipe size like this?

The pitless adapter (already installed) is a 1" stainless steel, the pump will be a Flint and Walling 1hp 7gpm. Total dynamic head, using 1" pipe in the calculations, comes out to about 365 feet, but with 1-1/2" pipe that will come down a bit due to lower resistance. Pipe from well to storage tank is 230' of 1" poly. No pressure tank, just filling storage.

Will 400' of 1-1/2" pipe hang OK on a 1" pitless adapter? I'll need to get reducers, etc., so the 1-1/2" pipe will be hanging on a 1" close nipple at the pitless adapter. I can swap out the adapter if necessary, or maybe get a sch. 80 or 120 close nipple for the hang.

Any other problems? I'm gonna have a pro with a boom truck do the install. I'm not messing with 1000 lbs of pipe.

 

[Valveman]

Even though it would be much heavier, the pitless should not have a problem. However, the velocity at 7 GPM will not be fast enough to take any sand or debris out of the well. It would just settle down in the pipe on top of the check valve untill there is enough to hold the check valve closed. Unless you are sure there is absolutely no debris in the well I would stay with 1".

There is no problem with larger pipe running horizontally, but vertical pipe being too large is a different story.

 

[Sponsor]

 

[Odysseus99]

Thanks Valveman, I didn't think of that. It's a clean well, the water comes from porous lava layers and serpentine, but above those layers for 300 feet is clay/sandyclay/silt. Not much of that will get in, but some will. I better swap my 1-1/2" for 1".

 

[Texas Wellman]

Never seen a sub set on stainless. How much is the pipe costing you out of curiosity? I say go for it.

 

[Odysseus99]

I'm embarrassed to say. It was in a geo-thermal well that failed because the steel casing broke, letting in a higher layer of cold water, making the well useless. So he pulled all the SS and put it up on Craigslist, I was Johnny on the Spot. He's a contractor and knows what it's worth, but he just wanted to get rid of it. I drove for 5 hours, in a snowstorm over a 7200 ft pass in the mountains, to get there first. As I was sitting there handing them cash, the emails were flooding in on Craigslist. Happens like that sometimes. On Craigslist you can set a tickler for if a certain item comes up for sale, which I did. Anyway, so much for my good luck and the seller's generosity.

Along with the 1-1/2" was 230' of 1", which is what I'm going to use because of Valveman's advice about velocity clearing sand and grit. So I'll sell the 1-1/2" and use that to buy the rest of the 1", the pump, wire, installation, and a steak dinner.