PEX Bend TOO Tight?

[Jim Stinnett]

I have a piece of PEX with an expansion fitting coming off a 90 and going into a drop elbow. The connection is at an angle and feels like there is a lot of stress at the fitting. Is this considered acceptable?

 

[Terry]

That looks fine.

 

[Sponsor]

 

[Plumber69]

The bend is fine. But being screwed in particle board. Id think that wing 90 will get floppy over time

 

[Jim Stinnett]

The bend is fine. But being screwed in particle board. Id think that wing 90 will get floppy over time

Thanks its actually a piece of Advantec 3/4 sub-floor with 2x6s behind it.

 

[Reach4]

The bend radius for Aquapex (PEX A) is 6 time the OD. That corresponds to a circle that is 12 time the diameter. For 1/2 inch Aquapex, that minimum circle diameter would be 7.5 inches. For 3/4, the minimum circle diameter would be 10.5. I drew that circle in red, and this illustrates you are OK, as stated.


For other PEX, the bend radius is 8 times the OD of the pipe.

 

[wwhitney]

From the 2019 Uponor Piping Systems Installation Guide, the top result here: https://www.uponor-usa.com/en/resou...stems%20Installation%20Guide&facets=[]&page=0

Cheers, Wayne

 

[Reach4]

From the 2019 Uponor Piping Systems Installation Guide

Oh, man, insomnia for Jim.

 

[wwhitney]

I think the lower bend could be straightened a bit at the pex-pex elbow, you wouldn't have to move the elbow much. Then a strap or two on the pipe would hold it straight at the elbow and make sure the bending stresses are in the middle of the pipe section rather than at either end connection.

It's also likely that it would take a lot more lateral stress at the joint to actually fail and that it's fine as is.

Cheers, Wayne

 

[Reach4]

It's also likely that it would take a lot more lateral stress at the joint to actually fail and that it's fine as is.

I think fine as is also.

If Jim were to try to manipulate that first two inches of the diagonal pipe to be straight, I think he would need to replace that piece of PEX with one maybe about an inch longer.

 

[Jim Stinnett]

Thanks everyone! This a great group and I really appreciate the feedback.