How to Install a Water Heater Expansion Tank?

How to Install a Water Heater Expansion Tank?

To install a water heater expansion tank, you must have all the required tools only then you will be able to complete this task successfully.

You might be thinking to call someone for this work but what about doing this DIY work at home with a bit of knowledge? This expansion tank is a device that is used for safety and might require a local building code for installation.

It is needed whenever you are about to install a new water heater tank or want to add protection to the previously installed water heater.

How to Install Water Heater Expansion Tank?

  1. Get your hands on all the important tools and supplies needed for this purpose.
  2. Turn off the water supply line and power supply before starting work.
  3. Now take the expansion tank and other accessories that you have purchased. The tank should compliment the unit.
  4. Make a connection from the cold water supply line.
  5. Drill a hole where you want to install the expansion tank near the water heater.
  6. Attach the tank and seal the connection with a wrench.
  7. Turn on the water supply line and power supply.
  8. Do not forget to examine the working of the expansion tank.

 

Working of Water Tank Heater Expansion

An expansion tank is one of the most important and useful accessories for your water heater that not only gives complete protection but also enhance the life of your heater.

Whenever the water heats up it expands and if no expansion tank is installed then it might result in plumbing system damage. If the water in the tank is heated at 50 to 120-degree temperature then it automatically boosts to 2 percent.

Working of Water Tank Heater Expansion

An expansion tank gives enough space for this water to stay. In closed plumbing systems, it is one of the most important things. The expansion tank also contains a flexible rubber diaphragm that comprises two different sections.

One section gives space to the expanded water while the other section gives an air chamber that pressurizes when the diaphragm enlarges into it.

That’s why it is important to get this expansion installed. Now you are familiar with the work, let’s move ahead and talk about how to easily install it in a few simple-to-follow steps.

Tools and Materials Required

Before starting the installation work ensure you have all the right and required tools and supplies so that you do not have to pause the work every time you are short of some particular tool.

Hence, the tools or materials, or supplies needed for this purpose are:

These are a few important tools that you must have beside you whenever you are about to start the installation work.

Methods to Install Hot Water Heater Expansion Tank

Before wasting the time, let’s jump directly to the important part of the guide i.e the installation method.


Before starting any electrical work, the foremost part is to shut off the main supply in order to avoid unpleasant accidents. You need to turn off the building’s supply line if the unit is attached to a line using a shut-off valve.

However, you have to turn off the breaker if it functions on electric power. If you have no idea better call someone for assistance instead of doing it yourself.


Now you have done all the safety precautions, it’s time to get your hands on the expansion tank that you have purchased along with all the basic accessories. However, you need to be careful while buying this tank.

Use the Expansion Tank and Accessories

It should compliment the unit and the size should be accurate so that you can easily fit it. To get the accurate size, measure the water heater tank twice and buy according to that size.

You also have to buy a tee fitting and plumber’s tape in order to add mounting brackets. All these accessories are important for the successful completion of the installation.


Now you have to make a connection in order to install the water heater expansion for which examine the cold water line that is horizontal. That line will help you in making the correct connection.

Examine the Cold Water Supply Line


In this step, you need a lot of tools because you have to drill some holes. Make sure to put the unit near the heater for which you have to place it above the cold water line pipe as already mentioned above.

Start the Installation of Water Tank Heater Expansion

Take a marker and mark the line on the wall and then start drilling the hole.


There is a connector attached at the bottom of the expansion tank. Get your hands on a plumber’s tape and enfold that spot. Now, you have to connect it to the tee fitting.

Attach the Water Heater Tank

Make sure the connector is too tightly attached that you find it tough to dislocate in the future. You can seal the connection with the help of a wrench.


As you are done with the connection, you can turn on the water supply and breakers. If the water heater functions on gas, fix the gas pipes and turn them on.

Turn on the Water Supply


Do not leave the work here because you also have to ensure that you have successfully installed it. Turn on the tap and check whether the water coming from the tap is hot or not.

If it is hot, you are successful but if it is not, you have done something wrong, Repeat the process.

How to Examine the Working of Expansion Tank?

Sometimes the expansion tank becomes damaged and you are unable to figure out whether it is working fine or needs to be replaced. The tank gets water from the tank using a diaphragm.

If the tank is located at the water supply line’s end, tap it on the bottom and top, if you hear any noise that is hollow, it indicates the expansion tank is working fine.

Examine the Working of Expansion Tank

On the other hand, if the sound is a thud, it means there is some issue in the diaphragm that needs to be resolved. Now check the temperature by touching the tank from the lower and upper parts.

The lower part should be warm because all the heated water is stored there but the upper part should be cold. If you notice the opposite, there is an issue in the expansion tank, get it fixed asap or you might need to do an expansion tank replacement.

Variations for an Existing Water Heater

If the water heater is already installed and you want to install the heater expansion, the biggest issue occurs when you have to find the proper space for the installation.

Sometimes, the space is too less that it requires numerous fittings and pipes in this regard. Sometimes you even have to change the copper flex pipe into a long or short one.

In some cases, you need to install the expansion tank near the water heater. You might have often seen plumbers or professionals install the hot water expansion tank by replacing the dielectric union because it is the only way you can get enough room for this new accessory.

This issue only occurs if the water heater tank is already installed.

Importance of Expansion Tank Installation

Are you wondering why you have to go through this entire mess or what benefits this accessory provides you with? Yes, it gives you numerous health benefits along with other features that depict why it is important to get them installed.

Sometimes due to water heating, a lot of pressure builds up and if you do not have enough room to store all this water pressure then it will result in a lot of damage.

It can provide harm to the valve’s regular operation and a lot of energy can be wasted. It can also decrease the life span of the unit and it might be harmful to your health as well.

One can not ignore the healthy safety feature this expansion tank provides you with. High water pressure can also result in numerous big and significant issues including tank rupture, leakage problems, bulging water heaters, and a lot more.

If you want to keep your water heater tank safe from all these above-mentioned problems, it is vital to install an expansion tank. If you do not have enough time to indulge yourself in the process, you can ask a plumber.

FAQs – Frequently Asked Questions

If some questions are bothering you regarding water heater installation and expansion tank for water heater installation, let’s clear them out by checking the below-mentioned queries.

Where Should an Expansion Tank Be Installed?

It is normally installed above the heater water tank or you can also install it near it. Usually, you install it vertically but you can also consider installing it horizontally according to the requirement.

Sometimes, you do not have enough space so install the expansion tank as required.

Can I Install an Expansion Tank Myself?

Yes, it is a simple process that can be done at home with the required tools and supplies and with proper knowledge. The easiest method is already mentioned above that will help you complete this task within a few hours.

What is the Proper Way to Install an Expansion Tank on a Water Heater Tank?

Switch off the main water supply and main power before starting the installation. Buy an accurate expansion tank that matches the unit. Now check the cold water supply line in order to make the connection.

Next attach the copper adapter and make it tight. Now connect the Expansion Tank Pipe and later attach an expansion tank near the tank water heater. Do not forget to examine the installation process to figure out whether it is perfectly done or not.

Do I Need to Install an Expansion Tank on My Water Heater?

It is important to install an expansion tank on the water heater because it gives enough room to the water that is expanded when heated. Moreover, it also provides you with different health benefits.

What Size Expansion Tank Do I Need for 40-Gallon Water?

For 40 to 60-gallon capacity, you need an expansion tank of 2 gallons if the supply pressure is 40-50 psi.

Final Thoughts

I hope now you understand how to Install a water heater expansion tank without anyone’s help. It doesn’t matter whether you have installed the heater tank already or you have to install it along with the expansion tank, it can be a DIY work with the right tools and supplies.

Due to a lack of time, you can also hire an expert who will charge according to the complexity of the work. I have mentioned a few best and easy methods that will surely help you to make the connection secure.

It is important to buy an expansion tank that is well suited to the unit so that you do not have to face size issues.

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