Connecting 3/4" poly to old PVC underneath well house

[Garn]

I'm almost sure there's nothing wrong with this plan, but before I commit to it, checking with people with more experience seems wise.

I'm in an area with a frost depth of less than 12". Around 24" underground is 3/4" PVC that used to supply a house that was on the property 20 years ago. Now all it feeds is an outdoor spigot next to the well house. I plan to run 3/4" 160 psi poly pipe the 60' or so to the house I'm building. Is there any problem with connecting the poly to the old PVC? The old PVC doesn't run toward the new house, so I would connect them a couple of feet in front of the well house using the brass insert to FPT adapter below with a male threaded adapter on the PVC. I could connect the poly to the piping inside the well house, but that would entail two elbows in the poly, and I would lose the outdoor spigot, which I'd like to keep, unless I also put a tee in the poly. It seems better to have just one fitting at each end of the poly than to add three more in between.

https://www.supplyhouse.com/Boshart-FA-075NL-3-4-FPT-x-Insert-Female-Adapter-Lead-Free

 

[Reach4]

How about https://www.supplyhouse.com/Spears-474-007-3-4-PVC-Schedule-40-Insert-x-Socket-Adapter

I don't have experience with the pvc insert adapter.

 

[Sponsor]

 

[Garn]

Thank you, Reach4. That would be simpler, and avoiding threads would be great, but almost everyone on this forum seems to indicate that poly has to clamp onto brass (or stainless steel, perhaps) inserts to hold reliably. Do you disagree?

 

[Reach4]

I expect any of the comments you read were regarding having a pump dangling down a well. Certainly I would want to avoid stressing the connection.

It's your well, so if it breaks, you won't get a $2500 water bill.

 

[Garn]

If the poly would hold reliably on a PVC insert in a relatively unstressed environment (buried 12" below the frost line), that fitting would be an excellent solution. I hope some of the people who have posted about insert fittings on other threads will see this and weigh in.

 

[Reach4]

If the poly would hold reliably on a PVC insert in a relatively unstressed environment (buried 12" below the frost line), that fitting would be an excellent solution. I hope some of the people who have posted about insert fittings on other threads will see this and weigh in.

Yes, that would be useful.

When you lay pipe, be aware there is expansion and contraction with temperature. So you don't lay poly taut and straight-- you snake it. See https://www.charlottepipe.com/Documents/PL_Tech_Man/ExpansionandContraction.pdf page 57. Your distances are short, so that is much less of a consideration. On the other hand, your temperature excursions will be bigger than most areas.

It would be nice if there were the equivalent of this for a pvc insert (SIDR) adapter. 3/4 pex is significantly smaller than 3/4 SIDR pipe, as you plan to use.
https://www.homedepot.com/p/Apollo-...le-40-PVC-Straight-Adapter-EPXPVC34/305469324

 

[Garn]

Thank you, Reach4. I had looked for an adapter with brass for the poly and PVC on the other end and couldn't find one. The selection of adapters for poly is surprisingly sparse at HD and almost every other plumbing retailer.

 

[Reach4]

If you do decide to go with NPT in the middle, I would consider schedule 80 PVC as being more robust. It would glue onto your schedule 40 pvc pipe, because schedule 40, 80, 120, etc have the same OD.

https://www.homedepot.com/p/DURA-3-4-in-Sch-80-PVC-MPT-x-Slip-Male-Adapter-C836-007/203511939
https://www.pvcfittingsonline.com/clearance.html
https://www.supplyhouse.com/Spears-836-007-3-4-PVC-Schedule-80-Male-Adapter-MIPT-x-S

Then feed that into an insert fitting with a FIP thread.

https://www.supplyhouse.com/Boshart-FA-075NL-3-4-FPT-x-Insert-Female-Adapter-Lead-Free

 

[Garn]

Thank you. I will consider it.