The expansion tank is an important part of your home’s water heater. Whether you have a gas or electric water heater, it probably features an expansion tank. As a homeowner, though, you might be unfamiliar with this otherwise common and important part. To learn more about the expansion tank and how it works, keep reading.
How the Expansion Tank Works
The expansion tank is a container that’s designed to temporarily store excess heated water. It looks like a small metal cylinder, and you can usually find it connected to the top or bottom of your home’s water heater. It’s known as an “expansion tank” because it supports the thermal expansion of water.
Water heaters become pressurized during usage. As it heats the water entering your home, the water heater will become pressurized due to thermal expansion. Heat causes water to expand. Water heaters, of course, have a limited amount of space, which is why they are often equipped with an expansion tank.
Your water heater’s expansion tank offers a safe place for excess heated water. If there’s too much pressure inside of your water heater, some of the heated and pressurized water will be diverted to the expansion tank. This process occurs automatically with the assistance of a diaphragm-like valve. Pressure will push the valve open so that water can travel into the expansion tank.
Do All Water Heaters Have an Expansion Tank?
While it’s a common part for most water heaters, there are some water heaters that don’t have an expansion tank. Tankless water heaters, for instance, generally lack this part. Most tankless water heaters don’t need an expansion tank because they don’t store heated water. They feature an open plumbing system that doesn’t require the use of an expansion tank. For all other water heaters, though, an expansion tank is needed.
Signs of Expansion Tank Failure
How do you know if your water heater’s expansion tank is failing? Leaking water is a potential sign of failure. Like water heaters themselves, expansion tanks shouldn’t leak water. If there’s a puddle of water underneath the expansion valve, you should consider getting it inspected by a professional technician.
Another potential sign of expansion tank failure is excessively hot or cold water. The expansion tank may store too little water, or it may store too much water. In cases such as these, you may notice that the water coming out of your home’s faucets is excessively hot or cold.