06/14/2016 0 Comment(s)

PEX Manifold

A PEX manifold is a control and distribution system designed for use with PEX tubing. PEX tubing is a durable and flexible pipe that is used for plumbing, heating, and potable water applications. Its flexibility gives the tubing the advantage of being snaked through walls and other confined spaces, resulting in fewer walls having to be broken into for installation purposes and future fixes. PEX tubing is also used for heating purposed due to its ability to handle high heat and pressure. A manifold is the basic zone of operations for any PEX system, and controls all the outgoing cold and hot pipes to their appropriate fixtures.  

In the plumbing and heating industry there are a few different variations of the manifold. A manifold is commonly made out of materials such as brass, stainless steel, copper, and even polyester to fit the criteria of it applications. Each type of manifold is used for different applications ranging from heating to domestic water supply. Continue below to learn vital information pertaining to PEX manifolds; including types, applications, and even step by step instructions on how to properly install a PEX manifold.

Manifolds by construction Material


■ Brass - Brass is a copper and zinc based alloy that is most commonly used for radiant heating purposes. Brass manifolds usually come equipped with numerous features such as valves and gauges. This type of manifold offers the consumer advantages of durability and easy installation.
Stainless Steel - Stainless steel manifolds are typically applied to the same applications as brass manifolds. They are widely renowned for being sold with a variety of pre-installed features, making installation and control a non-issue for the consumer. 
Copper - Copper manifolds are known for their durability and longevity. These manifolds have been used in the plumbing and heating world before there was an industry. Copper is believed to be one of the best choices when choosing a manifold due to its availability to be used with plumbing or heating applications. 
Polymer - Polymer manifolds are manufactured from a composite material. They are typically reinforced with a glass fiber via a fastening system. Many manufacturers have even started to distribute PEX polymer manifolds to coincide with their PEX plumbing or heating systems. Depending on the material of the polymer it may be used for heating and potable water applications.  

Manifolds by Their Applications

■ Plumbing - Plumbing manifolds have to be in compliance with specific state codes and federal laws. In the past decade a law has been issued prohibiting a lead count in any potable water materials. Due to this law most plumbing manifolds are either made from a copper or polymer type material. Those two types of construction materials are lead-free and can last a plumbing system an upwards of 50 years. 

■ Potable - Potable water applications result in any water that will be used in the act of drinking. 
Hot/Cold Water Supply - The water supply in a home contributes to everyday applications such as showers, sinks, toilets, washing machines, etc.
Heating - 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. When applying a manifold to heating applications such as radiant floor heating, hydronic heating, and snow/ice melting systems, the top choices are usually brass, polymer, and stainless steel.
Hydronic Heating - Hydronic is a process of heating in which water is heated to a certain degree to move the heat from where it is originally heated to where it is needed.
Radiant Floor Heating - Radiant floor heating is the process of heating a residence through radiation given out by the floor. This process is usually run through piping or mats under the floorboard or in-slab.
Snow/Ice Melting System - A snow melting system is designed specifically to melt and remove any traces of snow or ice. This application is typically set-up in slab and run with a mixture of water and glycol (anti-freeze).


How to Install a PEX Manifold for Plumbing

1. The first step of installing a PEX manifold for plumbing is to find an area that is near the center of all your applications and remotely close to a water heater outlet. 

2. The second step is to run all the PEX tubing from the manifold to its appropriate fixtures. The installer should be using two different color coded PEX pipes to distinguish between the hot and cold lines.  
3. The third step of the installation process is attaching the tubing. Using any connection method (Crimp, Clamp, Expansion, etc.), the objective is to connect the PEX tubing to the inlets/outlets attached to the manifold. Double check your connections to ensure they are tight and secure, lack of a solid connection can cause leaks.
4. The last step on installing a PEX plumbing manifold is to mount the manifold on the wall. Once the manifold has been set in place, attach the various PEX pipes to their designated outlets. Follow this step by connecting the plumbing manifold to the main water supply line.

PEX Manifold Systems for Plumbing

■ Home Run Systems - Home run systems utilize an effective approach to plumbing, allowing all the fixtures in a home to be connected to one manifold. This system is regularly used in residence where all the fixtures are located nearby. Utilizing this system requires a larger amount of PEX tubing as opposed to fewer PEX fittings.

■ Sub-manifold Systems – Sub-manifold systems are designed differently than home run systems in which they utilize more fittings than tubing to function. Sub-manifold systems are set up through the main water pipe which is then branched off at individual locations closest to the fixtures. 

How to Install a PEX Manifold for Heating

1. The first step of installing a PEX manifold for heating is placing the manifold directly in the middle of the residence. This will allow for easy distribution of the PEX tubing to all areas of the residence. Note: This area should be remotely close to a water heater, furnace, or boiler.

2. The next step is to run all of the PEX tubing to their designated areas of application. 
3. Once the tubing is run through all its designated zones, connect the PEX pipe directly to the manifold using a PEX connection.
4. Lastly make sure the tubing is connected to the manifold, mount the manifold on the wall and connect it to a water supply line.

Sizing PEX Manifold for Heating

Sq. Ft. per Branches w/ Radiant Floor Heating

2-3 Branches = 900 sq. ft. = 800-900 ft of PAP or OBP
4-5 Branches = 1200-1500 sq. ft. = 1000-1500 ft of PAP or OBP
6-7 Branches = 1800-2100 sq. ft. = 1200- 2100 ft of PAP or OBP
8-9 Branches = 2400-2700 sq. ft. = 1600-2700 ft of PAP or OBP
10-11 Branches = 3000-3300 sq. ft. = 2000- 3300 ft of PAP or OBP
12 Branches = Up to 3600 sq. ft. = 2400-3600 ft of PAP or OBP


OBP = Oxygen Barrier PEX Tubing

Components of a Manifold

■ Valves - Valves are connected to the manifold to allow and restrict the flow of water to specific zones.

■ Air Vents - Air vents are used to release air from the system, allowing the system to remain corrosion free due to its ferrous materials.
Adjustable Flow Indicators - These flow indicators are designed to ensure the correct distribution of flow in the system. They are used to achieve the designed flow rate.
Balancing Valves - The balancing valves are designed to control the amount of water flown through the tubing at any given time.
Temperature Gauges - Temperature gauges are used to monitor and show the temperature of the water in the system to make sure it is running properly.
Drain Valves - Drain valves are used to flush the system of excess water.
Compression Adapters - Compression Adapters are fitting used connect the manifold with the PEX tubing creating an air tight seal.
Thermostatic Actuators - These devices are used allow automatic shut-off either by room thermostats or electrical switch.


PEX manifolds have made the plumbing and heating industry that much easier. These devices allow homeowners to manage their systems down to the tee, providing easy access to all zones and fixtures. Many manifolds today are sold with a number of components mounted onto the system, making them easily one of the best items on the market. Controlling the heating and plumbing in a home has never been easier, and this progress will only continue to grow.