Here's some pics of my underground install. It's Badger 5-wrap inside of 6" SDR35 bell-end gasketed PVC. Top of 6" pipe is about 24" down with about 6" clean crushed limestone under it, and about a foot over the top, then about a foot of dirt over that.
I used a 3 1/2" core bit to go through the 8" concrete wall, of course I found and hit a piece of 1/2" rebar DEAD CENTER of my hole.
A 3" Sch40 PVC pipe fits that 3 1/2" hole (with a little persuasion), then I got an adapter to go from 3" Sch40 to 6" SDR35, worked slick.
I had to take some of the 5-wrap off to get the 2 1" pex lines through the 3" sleeve through my basement wall. I also removed the black perf tile on the end at the furnace and curved the insulated pex lines though a couple of 6" SDR35 45 degree bends to get it out of the ground.
I pulled some 12/2 Romex though the black perf tile using the provided pull string, and I also ran an empty 3/4" conduit for a just-in-case.
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