Crimping Pex onto Polybutylene Diverter Valve?

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Paulcmaine

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I am repiping my house which is currently all PB. The bathtub diverter valve appears to be a direct crimp unit, unfortunately. I don't have time to replace it.
Am I able to crimp pex directly onto the PB fitting? I could use either copper crimp rings or cinch clamps. I understand they are not meant to be compatible but this is my own home so I'm less worried about whether this is technically correct than if it will work and since PEX is slightly smaller ID than PB I'd think that if I can get it on there I would have a pretty good seal.
My other option would be to cut back the PB to an inch or two of pipe and use a PEX-PB crimp adapter. I'll be closing the wall back up so I'd obviously prefer to remove all the PB but since either solution is a bit of a hack I'd love to hear some opinions on which is less likely to be an issue over time.
IMG_9633.jpg
 

Tuttles Revenge

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As a professional I have zero experience attempting something like this. With that said, the diameters need to match up to use a typical crimp ring and crimper. The idea of the cinch ring might work better depending on if it will apply enough pressure uniformly as it cinches. I've never used that style myself.

Is there any way to unsolder the PB fitting from the valve?

If the fitting will be getting full water pressure, I would want to ensure its longevity. Probably wouldn't hurt to throw a battery powered moisture detector in the wall cavity before buttoning it up too. Battery will last a couple years or more.
 

Jeff H Young

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if the barb is legal for pex go for it. Rather than try to find out Id replace with a new barb .
 

Paulcmaine

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As a professional I have zero experience attempting something like this. With that said, the diameters need to match up to use a typical crimp ring and crimper. The idea of the cinch ring might work better depending on if it will apply enough pressure uniformly as it cinches. I've never used that style myself.

Is there any way to unsolder the PB fitting from the valve?

If the fitting will be getting full water pressure, I would want to ensure its longevity. Probably wouldn't hurt to throw a battery powered moisture detector in the wall cavity before buttoning it up too. Battery will last a couple years or more.
Oh thank you, good eye! I had thought that was a direct crimp fitting like some of the modern pex stuff, I didn't notice the sweat adapter. Will sweat it out and make a proper repair.
 

WorthFlorida

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I would not do it. If the fitting does not match the pipe type, a major leak to extreemly expensrive

Skarke bit does make a transitional fitting.
 

Reach4

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PB fitting is larger OD.

I am not a pro. I wonder if you could use a PEX A expansion connection on your PB barb. I don't find the OD diameter of the PB fitting barbs.

You could reinforce the ring by running a small worm gear clamp around the ring.

Your photo makes it look like the pipe is bulged out. Is it, or is that just an illusion from the photo?
 
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