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All-Purpose OWF Discussions => Plumbing => Topic started by: juddspaintballs on April 01, 2023, 08:31:48 PM

Title: Underground piping
Post by: juddspaintballs on April 01, 2023, 08:31:48 PM
I typically use Thermopex or similar for my underground piping.  I know all of the benefits of it.  I've done 4 installations with that type of pipe and one where I closed-cell spray foamed the PEX inside of plastic sheeting which also worked quite well. 


I'm about to build a house.  My retired builder friend suggested just running PVC in the ground and pulling my PEX through for the underground piping.  Am I crazy for considering this?  The air gap in there is insulation enough and as long as the PVC doesn't break, it should stay dry. 
Title: Re: Underground piping
Post by: juddspaintballs on April 09, 2023, 04:55:58 PM
Slow in here
Title: Re: Underground piping
Post by: OTR on April 10, 2023, 05:01:26 PM
I would not think that would be a good idea. Your pex will not be suspended in the middle of an air gap, it will be resting on the bottom of the PVC, which will be touching the ground and sucking your heat away.
Title: Re: Underground piping
Post by: juddspaintballs on April 10, 2023, 08:33:21 PM
I realize it would be resting on the bottom, but the actual amount of contact is minimal and the heat transfer from PEX through PVC and into the ground wouldn't be a ton. 


I'll probably just wind up using Thermopex so I can get it locally.  I'll be fine using the regular 1" stuff.  I don't have a need for high BTU transfer, just maintaining a radiant slab in a well-insulated house. 
Title: Re: Underground piping
Post by: OTR on April 25, 2023, 11:27:39 AM
I realize it would be resting on the bottom, but the actual amount of contact is minimal and the heat transfer from PEX through PVC and into the ground wouldn't be a ton.
I disagree, but I have no data to go by. That small bit of contact surface area will add up in a hurry.

Sounds like you're going to go with thermopex anyway.
Title: Re: Underground piping
Post by: hoardac on May 01, 2023, 05:45:50 PM
Insulate you will regret not doing it later.
Title: Re: Underground piping
Post by: juddspaintballs on August 29, 2023, 07:37:11 PM
OK, I'm getting 1" Thermopex from a local dealer.  $1564 for 100' after taxes.  That seems like more than I've paid in the past, but who knows what prices have done ever since the craziness of the past 3 years. 

Does 1" Thermopex use regular 1" PEX fittings?  Can I use 1" Sharkbites or 1" cinch rings on regular 1" fittings or is it a special size and need different fittings? 
Title: Re: Underground piping
Post by: Super44 on October 27, 2023, 02:37:15 PM
When I first installed my pipping I use Shark bites but have since replaced all but 2 of them with crimp rings.  The 2 still in the system will also be replaced when the leak.