What is a Water Heater Expansion Tank and Why Do I Need One?

Does your water heater need an expansion tank?

Chances are, the answer is yes. Yet, because expansion tanks were not as necessary in the past as they are today, you may not even know what an expansion tank is, let alone why you probably need one.

An expansion tank looks like a mini tank or boiler, and typically sits on top of or adjacent to the water heater. Expansion tanks are available in a variety of sizes depending on your water pressure, the size of the actual water heater, and the temperature the water is heated to.

As water is heated, it expands and its pressure in the tank vessel will increase if there’s no room for thermal expansion. The old domestic hot water heater plumbing systems were designed so that the expanding water in heaters would push some water back outside the house – into the public water main, which would absorb the pressure.

However, with changes in city ordinances and plumbing practices, cities are no longer allowing hot water systems to relieve built up pressure back into the city water supply. This pressure build-up now has no place to go, which can cause major issues with your water heater including failure or bursting. An expansion tank is needed to prevent these issues. View the infographic below to become familiar with the parts, pipes, and components of an expansion tank.

Prevent Permanent Damage to Your Water Heater With an Expansion Tank

All water heaters, regardless of whether they use heating oil, natural gas or propane or even electricity, can suffer the negative effects of thermal expansion as the cold water coming into the tank turns to hot heated water, increasing the overall water volume via expansion and increasing pressure inside the tank. This increase in volume and pressure must be relieved for overall safety.

What is an Expansion Tank?

Here’s where the expansion tank comes into play: when both sized correctly and installed correctly, it absorbs this “extra” water into a bladder, located inside the expansion tank, and minimizes excess pressure in the water heater unit.

Expansion tanks help reduce water hammer issues and help protect the plumbing system from stress and damage, which leads to longer tank life. To do their job, these tanks must be properly located, sized, piped into the overall system and should be checked annually.

Our heating and cooling technicians will make sure each expansion tank is correctly installed, and maintained, to prevent water hammer, high water bills and unnecessary wear on the water heater and plumbing fixtures.

If you’re concerned that your water heater doesn’t have an expansion tank, ServiceMark can help.

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What Causes These Plumbing Issues?

The hot water heater in your household is integrated with a check valve that is installed in the cold-water feed piping for efficiency and comfort. The check valve and pipes are referred to as a “closed system” by licensed technicians in the plumbing industry. The purpose of these one-way check valves is to prevent water from flowing backward out of the house through the supply pipes, which prevents possible contamination from getting into the public water supply.

The inherent problem with check valves placed in the system is that the water pressure builds up in the closed system until someone opens a valve. An expansion tank will prevent an explosion in your water heater due to high pressure. If your water heater tank has a check valve or pressure-regulating valve, we recommend investing in an expansion tank.

ServiceMark Can Install Your Expansion Tank!

At ServiceMark, our fully trained team of exceptional heating, cooling and plumbing technicians and support staff are ready 24 hours a day, seven days a week to help make your home not only comfortable but safe as well! We offer same-day service and certified technicians who arrive on time, every time, guaranteed. Call the ServiceMark team to ensure your home is safe and comfortable all year long.

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Our team of licensed plumbers will help you integrate an expansion tank with your water heater to prevent a leak in your house. We offer water heater repair and installation services in states such as Delaware, Pennsylvania, and Maryland. Our staff offers HVAC and plumbing services such as drain cleaning, air conditioning installation, furnace repair, and appliance replacement. We have been providing reliable and safe plumbing, heating, and air conditioning services to homes since 1951. Our licensed contractors offer extensive warranties to ensure satisifaction.

Our team of certified plumbers will connect an expansion tank to your water heater to prevent damage to the water tank and pipes.