What Is An Expansion Tank For A Water Heater? 3 Best Tips To Maintain It!

What is an expansion tank for a water heater? An expansion tank is an additional tank attached to a water supply for the water heater. These expansion tanks were designed to prevent excessive pressure in water when thermal expansion occurs where the water is heated in the water heater.

You might be wondering what that small tank connected to your water heater is supposed to be is? You may already have an idea that it is an expansion tank, and you might think that it’s just an extension for the water heater, but actually, it does more.

What is an expansion tank for a water heater

So if you have something like that together with your water heater, it is better if you know how it is used, or what is it for? How to maintain it and valuable anything about it. Lucky for you, this article has what you’re looking for. We’ll discuss everything about expansion tanks, from what it is, their purpose, and maintenance. So sit back, relax, and read up till the end!


What An Expansion Tank Is For A Water Heater?

So, what is an expansion tank for a water heater? These expansion tanks are a requirement if you have a closed-loop heating boiler system. So how do these expansion tanks work?

There are two types of expansion tanks—compression and Bladder type. A compression type is a plain steel tank that you usually mount horizontally above the boiler. At the same time, a bladder-type expansion tank or a diaphragm is to be placed at the bottom or on the floor. Its volume expands when water is heated, but it can’t be compressed. However, air could be compressed instead. The expansion tank uses an inert gas just like nitrogen to act as a cushion or spring against the pressure making it possible to maintain the water heater to work fine despite the pressure. 


Purpose Of An Expansion Tank For A Water Heater

One of the primary purposes of expansion tanks is what I already mentioned above: to help the water heater when the water pressure is produced from heated water. If the water pressure gets too high, it could damage the valves in your plumbing fixtures, the joints in your pipes as well as the water heater unit itself.

Thermal expansion always occurs in almost all substances, especially when heated. So the same thing happens when water is being heated several times in your home. Since water is non-compressible, the air pressure is compressed to the expansion tank instead so that the water will be pushed back out of the house. Although the pushing-back mechanism to relieve the pressure doesn’t work anymore because of check valves. The check valve is a one-way valve attached to a water supply to prevent the water from going in the wrong direction. The valve’s purpose is to keep the water flowing into the house through the pipes.

But since pressure builds up as water is heated from time to time, the expanded water will go to the expansion tank and be released only if the pressure settles down. However, if you noticed that the washers in your plumbing pipes wear out quickly, or there is a constant dripping from the relief valve on the water heater, you’ll need to take action.


Maintenance Of An Expansion Tank For A Water Heater

Of course, every unit must be maintained to be used for a long time. The same principle goes with your expansion tanks. You probably bought the expansion tanks together with your water heaters. These units usually have a warranty for professionals to take care of the maintenance if something goes wrong with the team. Although, what if that warranty expires? Here are some tips to help you maintain your expansion tanks and water heaters usable.


Tip #1. Check the pre-charge

Your plumbing system must be checked thoroughly by a professional at least once a year. This is to check the precharge of the system when the tank is empty. Maintaining a proper precharge will help inspection and allow air to escape making it easier to spot damages.


Tip #2. Choose the correct size

If you are plan to purchase an expansion tank for the system, make sure that you choose the correct tank size. An undersized or oversized expansion tank will significantly affect the performance of your water heater over time. This is especially true in bladder types of expansion tanks. The high water storage could cause the bladder tank to rub against the tank in every use, therefore, making it wear rapidly. So you have to make sure to get the right size.


Tip #3. Opening the system valve momentarily

Expansion tanks come with an anti-extrusion screen that holds back the bladder tank from forcing out the air from the tank. The elevated air charge could lead to a failed start-up of the tank. To solve this problem, you can open the system valve for a moment to release some of that pressure and stop the tank extrusion. You might also want to check out how to extend the life of your bladder expansion tank to know more about bladder tank problems.


It’s A Wrap!

Knowing an expansion tank for a water heater will help you and your water heater in many ways. One, it will help you be comfortable and leave your mind at ease to know what might cause the problems with both your water heaters and expansion tank.

I guess it’s helpful to read about when to replace water heater and how to get rid of a water heater.

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