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Can You Use PEX-B Fittings on PEX-A? (Explained)

Have you found yourself without the right fittings for your PEX-A pipe? You might be wondering if PEX-B fittings can save the day. Well, wonder no more because we have the answers you seek. So, can you use PEX-B fittings on PEX-A tubing?

The answer is yes. You surely can use PEX-B crimp or clamp connection fittings on PEX-A pipes using the same steps as installing these on a PEX-B pipe. However, this shouldn’t be a permanent fixture.

Are you excited to know why it is so? In the discussion below, we have covered everything that there is to know about this topic. Read on and find out.

Can You Use PEX-B Fittings on PEX-A?

In simple terms, yes, it’s possible to use PEX-B fittings on PEX-A. But there are some facts about  PEX (cross-linked polyethylene) that you must understand before diving into the specifics of using PEX-B fittings on PEX-A.

can you use pex-b fittings on pex-a

Understanding PEX Types:

PEX (AKA cross-linked polyethylene) comes in 3 types: PEX-A, PEX-B, and PEX-C. These types primarily differ in the way the cross-linking process is carried out during manufacturing.

PEX-A is highly flexible (according to a 2016 scientific study).

PEX-B, on the other hand, is slightly less flexible but still highly durable.

PEX-C has the least degree of flexibility among the three.

Now, the question at hand: Can you use PEX-B fittings on PEX-A tubing?

In theory, PEX fittings are typically universal and can be used with any type of PEX tubing, whether it’s PEX-A, PEX-B, or PEX-C.

So, yes, theoretically, you can use PEX-B fittings on PEX-A. However, it’s not as straightforward as it seems, and several factors must be considered.

Firstly, PEX-A tubing is more flexible than PEX-B, and it’s also more prone to deformation. So, when PEX-B fittings (typically made of brass or poly alloy) are used with PEX-A tubing, the softer material of the PEX-A tubing may not form a perfect seal with the fitting.

This could potentially lead to leaks over time, particularly under high pressure or temperature fluctuations.

In addition, PEX-B fittings often employ a crimp or clamp connection method. In contrast, PEX-A systems usually use an expansion method for creating connections.

As a result, using PEX-B fittings on PEX-A may require additional tools or steps in the installation process.

Let’s discuss this in more depth in the next section:

How to Use PEX-B Fittings on PEX-A?

Here’s a step-by-step guide on how to use PEX-B fittings on PEX-A tubing:

1. Check the Compatibility:

Before starting, make sure the fittings and tubing are compatible. Most PEX fittings are universal and can be used with either PEX-A or PEX-B tubing. But you must make sure the fittings and the tubing are of the same diameter specification as well.

2. Gather Your Tools:

You will need a PEX cutter, PEX-B fittings, a crimp tool, and crimp rings. Make sure that the crimp tool and crimp rings are of the appropriate size for the PEX-B fittings and PEX-A tubing you are using.

3. Cut the Tubing:

Use the PEX cutter to cut the PEX-A tubing at the desired location. Make sure the cut is precise and straight.

4. Insert the Fitting:

Insert the PEX-B fitting into the end of the PEX-A tubing. Make sure it is pushed in as far as it will go.

There should be no gaps between the fitting and the tubing.

5. Attach the Crimp Ring:

Place a crimp ring about 1/8 to 1/4 inch from the end of the PEX-A tubing and slide it on.

6. Crimp the Ring:

Use the crimp tool to crimp the ring onto the tubing and fitting. Make sure the crimp is tight and secure. Some crimp tools have a built-in “go/no-go” gauge that can be used to check the crimp.

7. Test the Connection:

Once the crimp is complete, check the connection to make sure it is secure. If the fitting can be twisted or pulled out, the crimp was not done correctly and should be redone.

In essence, installing PEX-B on PEX-A tubing is the same as installing PEX-B fittings on PEX-B tubing.

Although using PEX-B fittings on PEX-A tubing is somewhat acceptable, PEX-A native fittings and expansion tools provide a more secure and leak-resistant connection.

This is because PEX-A fittings are designed to be expanded with the tubing, creating a larger diameter that contracts around the fitting for a tight fit.

 If you need a more thorough guide on this, check out the following video.

Is It Safe To Use PEX-B Fittings on PEX-A for The Long Term?

No, it’s not suited for permanent or long-term usage. Here’s why:

Reduced flow rate: PEX-B fittings have a smaller inner diameter than PEX-A fittings. This means they will reduce the flow rate of water through the tubing.

Increased risk of leaks: PEX-B fittings rely on metal rings that are crimped or clamped around the tubing to create a seal. The “shape memory” of PEX-A tubing, on the other hand, enables it to shrink back to its original size after being expanded. 

This means that over time, the tubing may shrink away from the fitting, creating gaps and potential leaks.

Frequently Asked Questions

Let’s check some commonly asked queries regarding this topic:

1. Are there alternatives to using PEX-B fittings on PEX-A tubing?

There are some alternatives that are safer and more reliable than using PEX-B fittings on PEX-A tubing. These include:

1. Using a threaded transition.

2. Using a SharkBite fitting.

2. Can you use push fittings on PEX A?

Yes, you can use push fittings on PEX-A tubing, but they are not the best option for permanent or long-term usage. Push fittings are meant to connect PEX-A to other types of pipes with any additional rings or tools.

Therefore, push fittings are more suitable for temporary repairs or emergencies rather than permanent or long-term plumbing projects. If you need to connect PEX-A tubing to other types of pipes, you should use a threaded transition or a SharkBite fitting instead.


Finally, it’s evident that using PEX-B fittings on PEX-A tubing is not a safe or suitable method for long-term plumbing projects. However, if you want, it can surely be done.

Its downside is that it can reduce the flow rate and increase the risk of leaks. Instead, you should use a threaded transition or a SharkBite fitting to connect different types of PEX tubing. Or better yet, stick to one type of tubing and fitting for your entire project.

This way, you can ensure a more efficient, reliable, and durable plumbing system for your home.