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Knowing how to transition from PEX-A to PEX-B (or vice versa) is a highly useful skill if you’re a DIYer. Consider a home expansion project. If your house was plumbed in PEX-A, but you want your new addition in PEX-B, you’ll need to know how to make a permanent, quality connection between the two PEX types. So here are a few ways to connect PEX-A to PEX-B, along with the pros and cons of each method. (Spoiler: don’t use SharkBite!)

How to identify PEX pipe

The first thing we need to do is identify what type of PEX pipe we are using. There are two simple methods for identifying PEX pipe:

• Check the label. If you look closely at the pipe, you will see information printed on the side. PEX-A will clearly say PEX-A, while PEX-B will say — you guessed it — PEX-B. Easy peasy.
• The second way is to identify the style of fittings. PEX-B will have metal rings — either cramp or clamp — whereas the PEX-A uses an expansion ring made out of PEX or a similar material.

Now let’s look at how to connect PEX-A to PEX-B.

Method 1: PEX-B Insert-Style Fitting

This is our recommended method to transition: using a PEX-B insert-style fitting for both the PEX-A and PEX-B pipes. This method is quite simple. Since both sides of the transition will be insert-style, all you will need are crimp rings and a crimp tool. Boom. Done.

DIYers often ask about crimps versus clamps — which do we prefer? We prefer crimp rings. They’re a more reliable long-term solution. The clamp method is a little bit easier to install, but we have seen more clamps fail than rings.

Disclaimer: As a contractor, this insert-style fitting into PEX-A is not a manufacturer-recommended transition. It’ll work in the real world, but the manufacturer does not recognize this as a transition. So if you’re a contractor transitioning from PEX-A to PEX-B, you should ask the manufacturer about how they want you to make this transition Get it in writing, so it doesn’t void your warranty.

Method 2: SharkBite Fitting

Many customers and DIY plumbers have asked us about SharkBite fittings. So, do they work? SharkBite does make a coupling that connects PEX-A to PEX-B. However, we don’t recommend using them. Why? Because SharkBites in general are great for a temporary solution, but not for a permanent repair. Your PEX connections should be long-lasting — so we do not recommend SharkBite fittings as your permanent transition.

Method 3: Threaded Transition

Lastly, there is a threaded joint that will transition from PEX-A to PEX-B. If you’re a contractor who needs to have a certified joint, pay attention: this method is more likely to be manufacturer-recommended. There are two parts to this transition: the PEX-A MIP adapter and the PEX-B FIP adapter. These parts will thread together and allow you to join PEX-A to PEX-B. The PEX-A side will require an expansion ring while the PEX-B side requires the crimp ring. This method will also require using pipe dope and tape to ensure the seal is good.

While this is an effective method, there is a downside: it’s way more expensive than your standard PEX-B coupling. So, again — if you’re a contractor — make sure that it’s recommended by the manufacturer before shelling out the big bucks.

Summary

In this article, you learned how to identify PEX pipe, either by the pipe label or the connection style of your fittings. Next, we told you our recommended joining method: the PEX-B insert-style fitting with the crimp rings between PEX-A and PEX-B. This is a simpler method — and cheaper — method than the threaded adapter. Finally, SharkBite fittings are only effective as a temporary method, so we do not recommend them for this task. In any case, make sure you’re checking with the manufacturer if you need a warranty.

Have more questions about PEX-A and PEX-B? Check out our deep-dive article on PEX-A vs PEX-B, and the pros and cons of each. Good luck on your plumbing project!