What’s a Thermal Expansion Tank – And Does Your Water Heater Need One?

Water Heater MaintenanceA hot shower or bath should be relaxing and soothing. But a malfunctioning water heater can be a giant headache. Most water heater problems don’t just result in the unit shutting off – they can lead to a leak and significant water damage in your home. And one of the biggest threats to your water heater is excess pressure. Thankfully, there’s a plumbing solution that can deal with pressure problems: a thermal expansion tank. 

We understand that something called a “thermal expansion tank” sounds complicated and confusing. But it’s actually a simple device that can save your money and keep your home safe. Allow us to explain. 

Dangers of high pressure in a water heater

A simple rule of physics states that most liquids expand when heated. This is very important to remember with a tank water heater since it holds and warms 40 gallons or more at a time. If the tank is filled with cool water from the water supply line, and then that water is heated, space inside the tank can become scarce. At some point, something has to give – and the results are not pretty. The extra pressure can push on the walls and seals of the water heater, which will eventually leak or burst. The pressure can also weaken pipes.

How a thermal expansion tank works

As mentioned before, when water expands, that pressure has to have somewhere to go. A thermal expansion tank is an additional component that is installed between the cold water pipe and the water heater, and provides pressure relief when the volume in the main tank reaches maximum capacity. You can think of it as an overflow container that prevents excess water pressure from damaging the tank or plumbing.

Inside the thermal expansion tank, there’s a pressurized pocket of air that pushes the water back into the main tank when there’s room and it is safe.  

Signs that you need a thermal expansion tank

Not all homes need a thermal expansion tank attached to their water heater. But if any of the following apply to you, it’s something to consider to prevent costly repairs or dangerous situations in your home.

  • Your water heater leaks often
  • You’ve had to replace your water heater frequently
  • Your home has a backflow prevention device that reduces water contamination but restricts natural pressure relief

Water heater experts in New Haven and Fairfield Counties

Now that you know what a thermal expansion tank, the next question is, “Do I need one in my home?” The best way to find out is by contacting the experienced team at Rick’s Plumbing. We’ve been serving Milford and surrounding areas since 1992. To schedule a consultation on your water heater, call us today at (203) 874-6629.