PEX, or cross-linked polyethylene, is a flexible plastic piping that is commonly used for water supply lines in residential and commercial buildings. PEX has become increasingly popular in recent years as an alternative to copper and CPVC piping due to its flexibility, corrosion resistance, and ease of installation.
When installing a water heater system, an important consideration is what type of piping to use for the connections. Many homeowners wonder if PEX can be used to connect the water heater to the main water supply line and distribute hot water throughout the home. In most cases, the answer is yes – PEX is compatible for use with water heaters in both new construction and plumbing retrofit projects. However, there are some important factors to consider when using PEX with a water heater installation.
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The Benefits of Using PEX with Water Heaters
There are several advantages to using PEX piping to connect a water heater:
– Flexibility – PEX is flexible tubing that is easier to route through walls and ceilings compared to rigid copper pipes. The flexibility also allows PEX to expand and contract with temperature changes without cracking.
– Corrosion resistance – PEX is resistant to scale buildup and chlorine corrosion, which helps extend the life of the piping and allows for the passage of hot water without leaks. Copper is prone to pinhole leaks over time.
– Ease of installation – PEX connections don’t require soldering, so installation is quicker compared to copper which requires more time and skill to join properly. PEX tubing can make do-it-yourself plumbing projects more approachable.
– Freeze resistance – PEX has more freeze resistance than rigid pipes due to its flexibility. If water happens to freeze inside the tubing, PEX can expand without bursting.
– Cost – PEX is generally more affordable than copper piping. The flexibility of PEX also leads to potential cost savings in labor for installation.
For these reasons, PEX has clear advantages as an efficient and durable piping solution for water heater connections.
Using PEX with Tank and Tankless Water Heaters
PEX piping is compatible for use with all major types of domestic water heaters:
– Tank water heaters – PEX can be used to connect both electric and gas storage tank water heaters. PEX is suitable for the inlet and outlet connections.
– Tankless water heaters – PEX is approved for use with both whole-home and point-of-use tankless/on-demand water heaters that use either gas or electric power.
– Hybrid heat pump water heaters – PEX piping can be used with hybrid heat pump models that use integrated heat pump and compressor technology to heat water.
For any type of water heater, PEX can be used to distribute hot water from the appliance to supply lines, fixtures, and appliances throughout a building. This includes sinks, showers, bathtubs, washing machines, dishwashers, and more. The flexibility and durability of PEX makes it an ideal option whether in new construction or renovations.
Considerations When Using PEX with Water Heaters
While PEX is compatible for the majority of residential and commercial water heating applications, there are some important considerations:
– Maximum temperature rating – PEX tubing is generally rated for a maximum continuous water temperature of 180°F – 200°F before gradual material degradation can occur. Standard water heaters have a max set point of 120°F – 140°F, but higher tempurature units may require an additional heat diffusion or cooling system.
– UV resistance – PEX should not be exposed to direct, long-term UV light which can also degrade the tubing over time. Outdoor PEX line runs may need protection.
– Pressure ratings – Different PEX tubing comes rated for different maximum pressures, such as 100 psi or 160 psi. Verify pressure ratings match system requirements.
– Fittings – Use fitting types approved for use with PEX, like plastic PEX fittings or metal crimp fittings. Follow manufacturer instructions for proper PEX connections.
– Chemical sensitivity – Some chemicals at certain concentrations can cause deterioration of PEX. Check chemical compatibility before using with treated water systems.
– Code compliance – As with any plumbing system, PEX installations must follow relevant local plumbing, mechanical, and building codes for legal and safe operation.
Installing a PEX Water Heater Connection
When using PEX supply lines with a water heater installation, there are several steps involved:
1. Determine an appropriate location for mounting the water heater. This should be indoors close to the main water supply line. Make sure to allow clearance for water heater maintenance and sufficient ventilation.
2. Shut off the main water supply valve and open a hot water tap to depressurize the system. Turn off electrical supply to water heater if hard-wired.
3. Disconnect old water heater piping. Remove old water heater following any necessary drainage steps per manufacturer instructions.
4. Cut the proper length of PEX tubing needed for hot and cold inlet and outlet lines. Make sure to factor in some extra tubing. Mark lines for hot and cold.
5. Attach PEX tubing to water heater inlet and outlet fittings. Secure with approved PEX clamps, crimp rings or other connectors.
6. Attach PEX tubing for hot and cold inlet lines to main household supply lines. Connect outlet PEX tubing. Use necessary fittings and elbows for routing.
7. If needed, attach and wire water heater electrical supply, thermostats, sensors and other components.
8. Re-open main water supply and test for leaks under system pressure. Check for proper hot water flow.
9. Flush water heater per manufacturer instructions to clear any debris from piping.
10. Set water heater to appropriate temperature setting. Insulate any exposed PEX tubing runs.
Following proper PEX installation procedures and building codes is important for getting a leak-free connection that will last through the entire lifespan of the water heater. Calling in professional help is recommended if you are uncomfortable with plumbing projects.
Conclusion
In summary, PEX piping can generally be used for water heater connections with proper installation. The flexibility, durability, and corrosion resistance of PEX makes it well suited for the hot and cold inlet and outlet lines of residential and commercial tank or tankless water heaters. However, you do need to check that temperature ratings, pressure maximums, and chemical compatibility match your specific application. PEX must also be protected from UV light when routed outdoors. Following manufacturer instructions and plumbing codes for PEX water heater hookups is advised to get a leak-free system. With the right techniques, PEX can provide a reliable supply line connection to deliver hot water safely throughout your building.