Replacing well pump questions

[Mike56]

I'm going to be replacing my submersible well pump soon and have a few general questions. Well is 75' deep, 1" schedule 80 PVC threaded drop pipe/20' lengths, 3/4 hp. Pump has been in place for 35 years and never removed.
1) Can I reuse the 1" drop pipe or should I replace it?
2) The pitless adapter: will it be OK to reuse? If I have to replace the part connected to the drop pipe for some reason, are these a universal fit? The pitless is 4 to 5 feet underground.
3) Lastly, the well casing is 5" PVC (white in color). Is this special PVC for wells or is it schedule 40 or 80?
Thanks for any help!

 

[Reach4]

1. Reuse the PVC pipe, but if the couplings are pvc, you may want to replace with stainless. PVC couplings are good when tightened right, but the stainless steel couplings are less sensitive to overtightening.

2. Probably OK, but you want to replace the o-ring. Use Silicone grease, such as Molykote 111, or Release Compound #7. The release compound is lower viscosity, and also suitable for sliding seals as in softener pistons. Pitless adapters are definitely not standardize for the connection between the two pieces, but are pretty much standardized to NPT for the pipe connections, and 1-inch NPT is common for the lifting connection.

3. Tough one. It is probably schedule 40, but the connection between pieces can differ. But for what you are going to do, I don't see how that would matter, since the casing stays. If you were extending the casing, the OD of schedule 40 and schedule 80 are the same anyway.

Did the pump fail, or are you trying to do PM? The old pump may last as long as the new on.

I am not a pro, and I have somebody else do my well work.

 

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[Mike56]

Thanks, Reach. The casing question is because there's a bit of damage to the above ground section, i wanted to cut it and replace with a short section and a coupling. Looks to be standard S40 to me. OD measures for S40/80 OD
Replacing for PM. I figure 35 years is pressing my luck and I don't want it going out in the middle of winter.

 

[Reach4]

Thanks, Reach. The casing question is because there's a bit of damage to the above ground section, i wanted to cut it and replace with a short section and a coupling. Looks to be standard S40 to me. OD measures for S40/80 OD
Replacing for PM. I figure 35 years is pressing my luck and I don't want it going out in the middle of winter.

Schedule 4o pvc is available in solid or foam core. You want double- or triple-rated solid PVC, and not DWV-only. Similarly you need a pressure-rated coupling.

https://www.menards.com/main/plumbi...-pipe/pvc074000600/p-1444426396367-c-8571.htm is an example where they mention also good for casing.