How Thermal Expansion is Useful for Water Heater?

Tired of your water heater always leaking? Need to replace another heater and still don’t know what’s wrong? If so, you may need to install a thermal expansion tank for water heater. Before we go any further, let’s understand what a thermal expansion vessel actually is?

What is Thermal Expansion Tank?

A thermal expansion vessel is a safety device used to reduce the risk of voltage damage to the piping system. Because water expands when heated by thermal expansion, the water heater produces an additional amount of water each time it heats the water.

To be clear, an expansion tank does not increase the amount of hot water a boiler can hold. Instead, it forms a kind of pressure buffer to regulate the water pressure in your piping system – this can extend the life of not only the water heater, but also the entire water heater system.

The Problem With Hot Water Pressure

As you may recall from high school physics, most liquids expand as their temperature rises. As the temperature of the water in the water heater’s tank rises, so does its volume, pushing it with greater force against the walls of the tank.

The metals used in your water heater tank and the pipes in your home are naturally quite stiff. Therefore, it would continue to exert pressure on the tubes and sides of the tank unless the increased pressure had some sort of release.

In extreme cases, building pressure can cause the pipes to burst. But the most common result is that the water tank is deformed enough to break the rubber seals over time, leading to leaks and generally poor performance.

What is the Importance of Expansion Tanks?

Because water expands when heated, the overpressure in the boiler tank must escape. In the past, pressure forced water from the reservoir to flow into the water source it came from.

Today’s water supply is designed to prevent the backflow of water, the so-called backflow, through a check valve. The check valve prevents wastewater from returning from the inside to the water source, where it can contaminate the freshwater supply.

How a Thermal Expansion Tank Is Useful?

A thermal expansion tank is a type of housing that is attached to the cold water pipe that powers the water heater. Inside the metal housing is a rubber diaphragm and a compressed air bag.

When the water pressure rises, water can flow back to the expansion vessel. The flexible diaphragm allows water to enter the volume of the tank area, relieving the pressure of rigid piping. The air pressure ensures that the water is pushed back through the pipe system when it cools down.

In this way, the expansion tank acts as a shock absorber, relieving the increased pressure without damaging the pipe or tank.

How a Water Heater Expansion Tank Works?

The boiler expansion tank is another small tank that is connected to the water supply line of the boiler. The expansion tank is designed to handle the thermal expansion of water as it is heated in the boiler, preventing excessive water pressure.

If the water pressure is too high, it can damage the plumbing fixture valves, the supply line seals, and the water heater itself. The expanding water flows from the boiler into the expansion vessel, relieving the water pressure in the system.

What Happened if Water Heater Do Not Contain Expansion Tank?

Most homes with a non-return valve on the water supply do not have an expansion vessel because this was not necessary until recently. This may or may not cause excessive pressure build-up, depending on the specific design of the plumbing pipes in the home.

If you notice that your plumbing washers are rapidly deteriorating or water is leaking from your water heater’s vent valve, it may be a good idea to add an expansion tank. It can be inexpensive insurance against more expensive damage to your home’s plumbing system.

Thermal expansion Tanks and Old Homes

Homes built before the mid-2000s may not need a thermal expansion tank because no backflow preventers were needed in homes and the two-way water flow allows some natural pressure to escape.

However, backflow increases the risk of water contamination, so you may want to consider calling a plumber and assessing the risks and adding a backflow preventer and expansion tank if necessary.

Do you need to install an expansion vessel or do you have another problem with your boiler? Call Edwin Stipe, Inc. at (877) 337-8473 – our experienced service professionals are available 7 days a week!

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