PEX Manifolds and Stub Out Elbows

PEX (cross-linked polyethylene) tubing was invented in 1968 by a German scientist named Thomas Engle and introduced to the U.S. around 1980. The many benefits have made PEX tubing a popular choice for plumbing systems, such as affordability, flexibility, quick installation, and corrosion resistance. Plumbing the interior of a structure with PEX tubing can involve the inclusion of multiple parts that may make the installation process both organized and simplified. This could include the manifold and stub out elbow.

A PEX manifold provides a plumbing hub for modern, residential plumbing systems that distribute water to various zones throughout the structure. Many manifolds today are sold with a number of components mounted onto the system. Common PEX Manifold materials include brass, stainless-steel, copper, and polymer. Below are typical PEX manifold applications:

  • Hot/cold water supply – The water supply in a home contributes to everyday applications such as showers, sinks, toilets, washing machines, etc.
  • Heating – The majority of manifolds today are being installed for heating purposes. Their ideal construction allows them to safely run these systems through durability and corrosion resistance.
  • Hydronic radiant heating – A classic hydronic type radiant floor heating system is comprised by two or more loops (circuits) of PEX tubing, which are fed by the main hot water supply line from the boiler or other heating equipment. When a PEX radiant heat manifold is incorporated into a system, it helps to balance the flow in individual circuits, achieving equalized temperatures throughout the zones.

An elbow itself provides a bend in the line, thus changing the direction of water flow. Stub out elbows are primarily used when installing PEX pipe to stub out of the wall and allow for further connection of outlet stop valves and plumbing fixtures. This leads to a simplified installation, which saves on cost and labor. Stub out elbows are made of copper as this provides a solution that is rigid and resistant to bangs and bumps that could cause leaks. This plumbing part comes in a variety of lengths and inlet connections, is available in elbow or straight, and contains a one-piece solid body design. A stub out elbow can have a spun closed outlet or open outlet. The spun closed outlet makes pressure testing easy and prevents dirt and debris from getting inside pipes during construction. A wall/nail flange is also an optional feature for a PEX stub out elbow.

A.Y. McDonald offers a variety of PEX manifold and stub out elbows for multiple size and applications. Each option is made of no-lead brass material and adheres to the necessary plumbing standards (ASTM F1807 and ASTM F1960). To learn more about these plumbing products, take the AYU course called ‘PEX Manifold and Stub Out Elbows’, call A.Y. McDonald’s Customer Service Department at 1-800-292-2737, or fill out a Contact Us form on