Can I cement a CPVC fitting onto a PEX tube?? or can I use a compression fitting of some sort instead of having to do the typical crimping ???

NO! Pex cannot be glued and there are no compression fittings for cpvc, at least nothing that could ne used in the house. You will need to attach to each type of pipe, an adapter to pipe thread. The PEX adapter will be crimp or whatever that brand of PEX uses, and the CPVC adapter will glue on.

i can count on one hand the number of times i have worked with cpvc but i swear i have used a compression fitting on it. you can definately use compression fittings on pex. you need to insert a stainless stiffener(sp?) into the pex first.

I have used compression fittings on cpvc. Plastic ferrules came with the fittings.

This is lifted off the Harvel website
TRANSITION CONNECTIONS


Harvel CTS CPVC pipe can be connected to copper, brass, valves, and other piping materials using transition unions, compression fittings, specilty reinforced male and female adapters, and other readily available transition fittings. Follow the fitting manufacturer’s installation instructions for the specific connection being used to ensure a proper leak-free joint. When using compression fittings utilizing brass ferrules, it is recommended that Teflon® tape be wrapped around the ferrule prior to assembly to help compensate for differences in expansion rates between CPVC and metallics. Teflon® tape is also the recommended thread sealant for threaded connections. Certain pipe joint pastes and sealant compounds contain substances which could be damaging to CPVC and result in system failure. If joint sealant other than Teflon® tape is used, contact the sealant manufacturer for compatibility with CPVC. Caution must be exercised to prevent overtightening of threaded connections and compression fittings.





Peace out,

Kordts

This would also be a good application for a Sharkbite coupling-works on CPVC,copper and PEX.

Being CTS sized of course there are those push-on and other fittings, but you can't put those anywhere inside except maybe a stop valve under the sink, can you?

On PEX, I thought it had to be crimped, but I could be wrong. Wouldn't be the first time!

[www.cashacme.com]

Shark bites can be used because there is a small sleeve that self centers upon insertion of said tubing and offers internal support of the tubing. I don't think I would bury these fittings just yet, though. They haven't earned the trust!

Jason



Post Edited

Jason

On a similiar note, I know of one house where the owner glued cpvc fittings on polybutlyene pipe. They were on a gravity spring and the pressure was not very high. But it was in service several years with no leaks.

To join CPVC or copper to PEX I like the Qest compression (not insert) fittings.

They've been around for at least 25 years, are reliable and easy to install.

They have stainless steel grabers and believe me, once they hold onto the pipe they hold on tight.

I have a number of Qest compression fittings at my own house that are 18 years old, and they look brand new and have never leaked.

I have taken some apart 10 years after I first installed them to change some piping (I use them for piping by my well), and they were still very easy to take apart, and when I joined them back up were as good as new.

Don't use any teflon tape or any other compund with them.

In some plumbing codes though, any type of compression fitting may not be installed inside a wall. Only in "accessible" places. So check with your local codes.

See these fittings at:

[www.plumbingsupply.com]


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Regarding North Carolina Plumber's comments:

"...., I know of one house where the owner glued cpvc fittings on polybutlyene pipe.........and the pressure was not very high."

Shell company, the company that made ALL the resins for the Polybutylene pipe manufacturers, clearly stated that PB should never be glued. The composition of it made it impossible to be solvent welded ("glued" in layman terms).

It is my understanding that although PEX and PB have quite a different product composition, no manufacturer of the resins (there are many), nor any manufacturer of the pipe (there also are many of these) state that you can "glue" (solvent weld) PEX.

Yes, maybe using a multiglue on very low pressure pipe might make it appear that is "working" but ultimately the joint will fail with any significant pressure or movement.

Don't consider this a general recommendation for residential plumbing of any kind, but I want to offer up to the community an experience which differs from most of the responses here.

I have successfully (no leaks) solvent welded pvc to pex. The scenario was schedule 40, 1/2" pvc pipe to 1/2" Pex in a liquid low flow ~10 psi application. The pex happens to fit snugly into the pvc as male, and with about 1-1.25" of engagement welded up similarly to a normal pvc fitting. Not sure if this holds true with other sizes.

I'm not totally confident in the long term, but for many cycles of operation it has remained reliable.