Most people have them, and yet many of them can’t identify it by name. Well, it’s that “thing” that sits on top of your Water Heater Expansion Tank that resembles a propane tank but isn’t. Instead, it’s a water heater expansion tank which plays a vital role in the water heating process.
Here’s more about what they do and how to look for signs of trouble.
What Is It?
A standard residential expansion tank is similar in size and shape to a propane tank, like the one you may have connected to your gas grill. It has an air valve on the top like you’d see on a car tire. On the bottom of the tank, you’ll find a threaded pipe connection.
How Does It Work?
When water is heated, it expands. Think of boiling water in a tea kettle – the pressure inside the kettle causes it to blow out steam and your kettle to whistle. While the water inside a water heater doesn’t get nearly that hot, it too expands as it’s heated, resulting in extra pressure. With nowhere to go, that pressure gets trapped inside your home’s plumbing system, putting stress on water-using appliances, fixtures, and supply lines. Expansion tanks are designed to absorb that excess pressure.
Half the tank is filled with water from your home’s main water supply, the other half with compressed air, with a rubber bladder in the middle. As the water in the water heater tank heats up and expands, it pushes up against the rubber bladder causing the air inside the expansion tank to further compress, thus absorbing excess pressure.
How Long Does an Expansion Tank Last?
There are many factors that determine the lifespan of an expansion tank, including tank quality, water quality, proper inflation, and more. Some fail in as little as 2 years while others can last 7 years or more.
Signs of Failure
Most expansion tanks will fail in one of two ways. First, the rubber bladder will erode until the tank can no longer function. Or, the connection between the tank and water pipe will corrode and begin to leak.
If your expansion tank is showing signs of wear or your water heater isn’t equipped with one, contact Eagle Service Company so we can ensure you have the most reliable source of hot water possible.
