When we think back to our old science classes, it’s easy to remember that heat rises and water freezes at 32 degrees Fahrenheit. But do you recall what happens to water when it’s heated? If you said that it expands, then you get a gold star.
Thermal expansion is when any matter changes its shape, area, and volume when the temperature changes. For water, that means the volume increases when it is heated. How does this relate to plumbing? Let’s consider your water heater
How thermal expansion affects a water heater
Traditional tank water heaters hold between 30 to 80 gallons of water at a time. Cool water enters the unit, it’s heated, then stored in the tank until needed. Many water heaters are closed water systems, meaning that water comes in but a one-way valve prevents it from going back out to the water supply line. So when the water is heated, it’s going to expand and needs some place to go.
Signs of thermal expansion problem
In the majority of cases, water heaters and local plumbing codes are designed and prepared to handle the thermal expansion of water. But issues can arise, and too much pressure inside the water heater tank can cause a handful of issues, some potentially dangerous:
- Broken pipes
- Bulges in top or bottom of tank
- Relief-line leaks
- Leaking or busting water heater
Ways to handle thermal expansion
One safety measure that every water heater should built-in is a temperature and pressure relief valve. This device will expel water if the temperature or pressure gets too high inside the tank. This is good in the moment but doesn’t really address the root issue – temperature changes and water expansion.
To effectively fix this issue, a water expansion tank can be installed to your water heater. This is an additional vessel that takes overflow water when the main tank reaches its maximum capacity. The expansion tank prevents pressure from building up, which can reduce the risk of damage to the water heater, pipes, and plumbing fixtures throughout your home.
When to call a professional plumber
If you’ve noticed that your water heater doesn’t look or work the way it should, it may be a good idea to have it checked for a thermal expansion issue. The last thing you want is for your water heater to fail, leaving you with a cold shower, a giant mess, or a dangerous situation in your home.