New engineer with well piping transition question

[Chet McKinnon]

Hi all,

I'm new to well design/common practices so I apologize if what I'm asking is simplistic and/or of incorrect thought process, but what I'm looking at doing is designing a piping system for an 8" well that has a capacity of ~75 gpm and TDH of 355. The pump I'll be using is a Grundfos 75s100-16 which has an outlet of 2" NPT. That being said, the pipe I plan on using for the rest of the system is 3 Nom Sch 40 HDPE so I'm unsure of how to go from the 2" drop pipe to the pitless adapter, then to the 3" HDPE pipe.

I was thinking I could simply thread an HDPE reducer into the adapter and then weld the 3" end of the reducer to the 3" HDPE piping that leads out to the rest of the system but am not sure if there's a better way of going about doing it.

There are flanges you can purchase separately and attach to the 3" HDPE but I'm unsure of how I would do that to the adapter. I was hoping I could attach a flange to it but am not sure how that would work since it would need to align with the flange on the larger diameter pipe. Are there adapters that have an inlet of 2" and an outlet of 3"? The research I've done thus far tells me the drop pipe and the service line need to be the same size.

Any advice?

 

[VAWellDriller]

You can get a Baker industrial pitless unit and order whatever drop and discharge size you want.... an 8" unit comes standard with 3" drop and discharge....

 

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[Valveman]

A 2" pitless should have regular 2" NPT female threads. I would just use a 2" X 10" nipple, a 2X3 threaded busing, then screw on a 3" flange. Then you can weld a 3" flange to the HDPE and bolt it to the flange coming off the pitless.

 

[Chet McKinnon]

Awesome, I had hoped it would be that easy. Thank you for your input.