Can You Use Pex B Fittings On Pex-a?

Pex tubing has become a popular choice for plumbing heating systems because it is easy to install flexible resistant to corrosion. There are several types of Pex tubing in the market including Pex-a Pex-B. However one common question among homeowners plumbers is whether they can use Pex B fittings on Pex-a tubing or vice versa.

Pex Tubing Basics

Pex tubing is made of cross-linked polyethylene commonly referred to as Pex. The tubing comes in different dimensions such as ½ inch ¾ inch 1 inch is color-coded for easy identification. Pex-a Pex-b tubing differ in how the cross-linking is achieved.

Pex-a Tubing

Pex-a tubing also known as Engel-method tubing is cross-linked using a process called the peroxide method. This process exposes the polymer to high temperatures pressure creating a uniform consistent cross-linking.

Pex-b Tubing

Pex-b tubing also known as Silane-method tubing is cross-linked using a different method. In this case the polymer is exposed to irradiation or chemicals that activate a cross-linking agent present in the polymer. This method is less expensive less time-consuming than the peroxide method used for Pex-a.

Compatibility Between Pex-a Pex-b Fittings

Although both Pex-a Pex-b tubing are made of cross-linked polyethylene they have different characteristics that affect their compatibility with fittings.

Pex-a Fittings

Pex-a fittings are designed to work with Pex-a tubing. They are usually made of brass or stainless steel have expansion rings that grip onto the tubing when heated. The expansion rings create a watertight permanent connection that does not leak or degrade over time.

Pex-b Fittings

Pex-b fittings are designed to work with Pex-b tubing. They are also made of brass or stainless steel have crimp rings that compress onto the tubing when crimped. The crimp rings create a secure connection that is also watertight long-lasting.

Compatibility Issues

Using Pex-b fittings on Pex-a tubing or vice versa can cause compatibility issues that can lead to leaks or failure of the connections. The expansion rings used with Pex-a fittings are larger in diameter than the crimp rings used with Pex-b fittings. If Pex-b fittings are used on Pex-a tubing the crimp rings may not hold onto the tubing securely leading to leaks or separations. Likewise if Pex-a fittings are used on Pex-b tubing the expansion rings may not fit properly because they are too large also leading to leaks or separations.

Conclusion

In conclusion it is not recommended to use Pex-b fittings on Pex-a tubing or vice versa. The compatibility issues can cause leaks or failure of the connections which can lead to costly repairs or replacements. To ensure a successful Pex installation use Pex-a fittings with Pex-a tubing Pex-b fittings with Pex-b tubing.