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Can I Use PEX for Water Heater? (All You Need to Know)

Crosslink polyethylene or the Pex is an excellent component used in pipings, electric cables, water piping, and many other electric & non-electric systems. Pex is durable and ensures the best protective and flexible layers of the fittings.

You can use it everywhere to get the perfect fittings and eradicate the complexity. Fittings, including water piping and electric cables, are the best-suited area for using the PEX.

Can I use PEX for water heater?

You cannot directly use the Pex for a water heater. It needs some modification and extra piping. You can only use Pex in your water heater after extending a pipe for about 18 inches. The distance must be measured accurately; only then you can use the PEX for water heater piping.

If you have a hot water heater, you must know some codes and requirements. You must follow them to get the secure water heater. One of the best and must-follow requirements is PEX use. You cannot directly use the PEF for a hot water heater.

It must go through an extended pipe, and there should be a minimum distance that you must maintain while installing the PEX. Otherwise, the fittings will be faulty, and you won’t find any particular solution to use the PEX directly into the water heater.

It will be a threat and unsafe practice for your heater. And the PEX cannot go through directly because of some constraints. However, some advantages force people to use the PEX on their fittings instead of the copper and other quality cables.

Let’s see if you can use the PEX for these water heaters or if you need some modification like before.

Connecting PEX directly to electric water heater:

Connecting PEX directly to an electric water heater is not an ideal practice.

You should never do it for any reason. There must be a third-party pipe or the coverage between the PEX and your electric water heater.

Although some people use the PEX directly to their electric water heater, it’s not a safe practice. PEX is not metal made cable or pipeline that you insert directly. You should maintain some requirements before using them directly.

PEX for tankless water heater:

Although you can use PEX for tankless water heater, it’s not an ideal practice. You should use an extended pipe and maintain a minimum distance from the vent.

Otherwise, the PEX might create electrical risks and will ruin the entire structure of the tankless water heater.

PEX for gas water heater:

Nowadays, the gas water heater is becoming a popular heating machine that uses the gas to heat the water for a while.

It works based on physics theory known as convection. However, the PEX is not ideal for your gas water heater.

You can only use the PEX by installing a new pipe on the water heater and then maintaining a minimum of 6 inches from the vent. Also, you should check your state codes and requirements before installing the PEX for a water heater.

What are the codes and requirements for using PEX pipe for water heater?

You must maintain some codes and requirements to use the PEX in your water heater. You cannot use the PEX in every state since it is not permitted everywhere for safety purposes.

Therefore, I have come up with three significant codes and requirements that you must maintain while dealing with the PEX pipe for the water heater. You must maintain them; only then you can use them for the water heater.

ASTM F 877 (Temperature):

Make sure that you don’t use it in places where the temperature of the water could reach 180°F at 100 psi unless it’s approved by the code, like a water heater relief line.

See what the manufacturer says about operating at higher temperatures at lower pressures.

It needs to be able to burst at 73°F and 180°F, stay under pressure for 1000 hours, and be exposed to high temperature and pressure for 30 days to make it look like a water heater isn’t working.

ASTM F 1807 (Fittings Materials):

This standard says which materials can be used to make these fittings, and it says how big the insert or barbed part of the fittings should be.

It also tells you what size copper crimp rings are and what kind of material they are made from.

In this code, these fittings must meet the performance requirements for PEX systems when they are tested with a PEX tube.

ASTM F 2159 (Material Quality and Size):

When it comes to plastic inserts and crimp fittings, ASTM F 2159 is the rule.

This standard tells you what materials and sizes are okay for the fittings. These requirements can be used to see if it was good.

Fittings must meet the performance requirements for PEX systems when they are tested with a PEX tube.

For water heater connectors, flexible metal water heater connectors may be required in some cases. Therefore, you must know the rule before installing the PEX tube in your water heater.

Can PEX be used for water heater pressure relief valve?

The PEX can be used for a water heater pressure relief valve. It is rated and instructed to use on the temperature & pressure relief valve. It will be a great fit in those places and will become a great fit too.

Since the PEX is made with high-quality material and a flexible deformation system, you can use it everywhere. You need to check the compatibility and the codes of requirements because of the safety concern.

If your water heater doesn’t allow you to use the PEX, you should avoid using it on the pressure relief valve. Although the manufacturer also suggests using the PEX over the valve, you may find some specific heater that doesn’t come with compatibility.

How far does PEX need to be from water heater?

The distance depends on the manufacturer’s requirements. You may ask your seller to suggest the safest distance for using the Pex. Generally, the PEX needs to be 6-18 inches far from the water heater vent.

Most people follow the 6″ instructions and they are using it safely without facing any complexities. If you want to ensure the highest-safety, you may go for the 18″ distance role. It would be the highest distance between the PEX and the water heater.

Before installing the PEX into your water heater, you must check the requirements and codes. You must be sure that the water heater is compatible with your PEX. Then, you can consider the distance.

What temperature can PEX withstand?

The PEX can withstand 200 degrees Fahrenheit. You cannot exceed the limit of your pex tubing, but the recommendation would be to keep the temperature around 150-180. This is the ideal temperature that your PEX can successfully resist.

Since PEX is made from Polyethylene material, it can resist heat as per your needs. Therefore, you should never find any issues using the Pex in your water heater. The average water heater temperature should be around 140°F, which is bearable to PEX.

So, the temperature resistance is another prominent feature of the PEX, and it shows why you can use the PEX in your water heater, although it’s made with Polyethylene material. The average water heater temperature won’t damage the PEX in any way.

How much pressure will PEX withstand?

Generally, a PEX can endure a pressure of around 800 psi because it is made by maintaining the official standard of ASTM.

This is supposed to be twice the prerequisite for the standard particular for PEX tubing. PEX fittings are regularly utilized for water transmission frameworks.

These transmission frameworks are continuously taking care of water tension inside the fittings. Accordingly, PEX fittings need to deal with the tension appropriately, or the framework might fall flat.

So its ability to withstand the pressure for use should be of an ideal standard to meet consumers’ needs as expected.

What size PEX is used for water heater?

Depending upon its use, a PEX for a water heater is like 3/8-inch to 1-inch for residential applications.

For a sufficient water flow, it is wise to introduce 1/2-inch or 3/4-inch PEX for your principle lines. The standard while supplanting old water supply lines with PEX is to utilize a similar size.

The more noteworthy the separation from the complex to the installation, the more extensive the PEX tubing ought to be. In general, if you use PEX about its standard sizing for a water heater, that will help you serve the best possible way.

Final thoughts

Although PEX is not a recommended material or piping for water heaters, you can use PEX by maintaining some requirements. There must be a minimum distance of 6″ between your PEX pipe and the water heater vent. Then, you should use an extended tube to install the PEX.