Using Abandoned Copper Pipe For PEX Chase

[DIY Lemon]

Hello Everyone,

I am in the process of repiping my house in Uponor PEX due to pinhole leaks in the existing copper.

I have been struggling to find an acceptable solution to route new PEX supply lines to the kitchen sink which is located on-slab and placed on an exterior 2 X 4 wall.

Currently the kitchen sink is supplied by a 1/2” copper branch that opens up into 3/4” soft copper for its run underneath the slab. The length of pipe underneath the slab is approximately 8’.

Instead of rerouting the supply to the exterior wall, would it be advisable to use the 3/4 soft copper line as a chase for new 1/2 PEX after it has been drained?

My main goal is to avoid a line freeze if it ever decides to get cold enough here. Apologies if this has been asked before.

Thanks!

 

[Reach4]

Instead of rerouting the supply to the exterior wall, would it be advisable to use the 3/4 soft copper line as a chase for new 1/2 pex after it has been drained?

That would be really nice, if it works. I would probably feed an electrical snake thru first to test the path in an easy way.

If it went easily , great. If not, I would feed some strong cord, like parachute line, thru using the electrical snake. I would also feed that cord through the PEX, and tie it off to something bigger than the PEX. Then I could pull the cord while somebody pushed on the PEX.

Maybe you could taper the leading edge a bit to take the square edge off, and then cut off the PEX straight, once you make it through.

I don't know what I would use for a lube. Maybe some dish soap diluted a bit. Maybe wire pulling compound. Maybe nothing would be needed for lube.

I have fed 1/2 Aquapex through a couple feet of bent 1/2 EMT conduit (0.622 ID) for use as a custom bend radius and support. 3/4 copper sounds pretty easy, except you would be going a lot farther. And maybe there is a bend that is not as big of a radius as you would hope.

 

[Sponsor]

 

[DIY Lemon]

That would be really nice, if it works. I would probably feed an electrical snake thru first to test the path in an easy way.

If it went easily , great. If not, I would feed some strong cord, like parachute line, thru using the electrical snake. I would also feed that cord through the PEX, and tie it off to something bigger than the PEX. Then I could pull the cord while somebody pushed on the PEX.

Maybe you could taper the leading edge a bit to take the square edge off, and then cut off the PEX straight, once you make it through.

I don't know what I would use for a lube. Maybe some dish soap diluted a bit. Maybe wire pulling compound. Maybe nothing would be needed for lube.

I have fed 1/2 Aquapex through a couple feet of bent 1/2 EMT conduit (0.622 ID) for use as a custom bend radius and support. 3/4 copper sounds pretty easy, except you would be going a lot farther. And maybe there is a bend that is not as big of a radius as you would hope.

I was able to pull the 1/2” PEX through with no issues at all. I did make sure to deburr the inside of the copper pipe ends extremely thoroughly and I blew the empty lines out with an air compressor. Kinda nice to luck out once in while ;-)

Thanks for the tip about the custom support bends you made out of emt. That will come in handy.

 

[Jadnashua]

The manufactured support bends are cheap, and you don't thread the pipe through, they are installed on the tubing in seconds. There's no risk of scoring the tubing with one, either.

 

[Reach4]

The manufactured support bends are cheap, and you don't thread the pipe through, they are installed on the tubing in seconds. There's no risk of scoring the tubing with one, either.

Why would you post that? Do you think that bend support that you described will work in all cases? Did the word "custom" elude you?