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Plumbing Manifolds

Control centers for hot and cold water that feed flexible plastic supply lines to individual fixtures

View the ToolBase TechSpecs - Home Run Plumbing Systems PDF file for an overview of this technology.

Plastic plumbing manifold

A new method for residential water distribution is gaining acceptance in the home building industry. Manifold plumbing systems are control centers for hot and cold water that feed flexible PEX supply lines to individual fixtures. Manifolds together with plastic piping offer installation-related cost advantages over conventional rigid pipe plumbing systems.

Separated manifold chambers or separate manifolds can serve hot and cold water lines. The cold water manifold is fed from the main water supply line and the hot water manifold is fed from the water heater. Water pressure in manifolds is maintained by the incoming service line. A water line dedicated to each fixture eminates from a port in the manifold. Manifolds can be centrally located at the water service line entry point, or in larger homes or aparment buildings, mini-manifolds can service remote fixture groups.

A Rehau copper plumbing manifold. Photo credit: NAHB Research Center

Manifold systems can accept all common supply line sizes, down to 3/8-inch. Typically, a parallel supply line layout or a hybrid version of this will be used with a manifold, so fewer fittings are required (hence, less pressure drop occurs in the lines.



Affordability

Because of its relatively easy installation, this system can save on labor costs.

Quality and Durability

Manifolds are corrosion resistant and make service relatively simple. Flexible PEX piping is also a better insulator than copper and not susceptible to rust.

Safety and Disaster Mitigation

Because all the connections are visible at either the manifold or the fixtures in a parallel or home run system, leaking is easily controlled. In addition, turning off the supply can be done at a central location.


Not-so-easy

Manifold systems are available for commercial distribution nationwide. Manifold systems require planning to determine optimal manifold location and routing of branch lines.


Cost of a manifold plumbing system will vary depending on number of ports, whether they include gate valves, and the material they are made from. Prices range from $35 to $200 plus.


Not Applicable


Premanufactured plastic manifolds should bear an IAPMO or other approved certification agency approval. Copper and brass manifolds often require field installed gate valves and can be purchased in four to twelve port versions. Manifolds must be mounted where they are easily accessible and valves must include labeling as to fixture location.


Model reMODEL: Philadelphia, Pennsylvania

Oakwood Homes: Green Valley Ranch. Denver, Colorado


Plumbing manifolds are mounted in a convenient, accessible location, such as a basement wall or a service closet, to allow access for shut off to individual fixtures. Minimum clearances of 36-inches (vertical) and 18-inches (horizontal) are needed between a thermoplastic manifold and a water heater. Opposing port manifolds can be mounted conveniently between stud framing.


Manifolds carry warranties of 0 to 10 years after the date of installation, dependent on the material.


Plumbing manifolds and parallel supply systems can be installed more quickly than rigid plumbing systems with fewer hidden fittings. The systems permit several fixtures to be used simultaneously without dramatic pressure or temperature drops.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.