Water Heater Overheating: Causes and Course of Action

Every house needs hot water, but water that is too hot can be dangerous. If the water temperature from your faucet is too high, there could be a problem with your water heater. Keeping your water heater at a high temperature can cause overheating, heater damage, and costly repairs.  The team at Core Plumbing put together this article on overheating water heaters. We will talk about what causes water heater overheating and how you can fix the issue.

How Does a Water Heater Work?

Modern homes use two main types of water heaters: gas and electric. Gas water heaters, as the name implies, run on natural gas. The burners heat the water, and pumps send it to the various taps and faucets around your house. Electric heaters use electricity to heat the elements and raise the water temperature in the tank. Electric heaters are cheaper to install but more expensive to run than gas heaters.

Causes of an Overheating Water Heater

Temperature Settings

Most water heaters have a dial that lets you set the water temperature. On most models, you can set the heat between 90- and 120 degrees F. If your water is constantly too hot, then your heater settings might be too high. With electric heaters, you can change the built-in thermostat to the desired temperature. For gas heaters, you will need to adjust the gas vent to control the temperature. If you adjust your water heater setting, but the problem persists, then your temperature probe might be broken and need replacing.

Broken Thermostat

Modern water heaters use a thermostat to automatically turn the heater on and off when the water reaches a certain temperature. Normally, a safety shut-off will turn off the heating elements if the thermostat sensor fails. Electric furnaces typically have a reset button that will turn the thermostat off in case of a malfunction. However, this safety feature can sometimes fail, leading to excessively hot water temperatures. If your thermostat fails, you will need to replace it with a new one.

Sediment Accumulation

All water has some level of dissolved minerals, such as calcium, magnesium, sodium, iron, and more. While some water sediment is usually a good thing, too much sediment can settle on the bottom of the tank and clog the heating element. When the heating element is blocked, it won’t be able to sense the temperature properly. This can lead to overheating as the element doesn’t know when to turn off. Sediment accumulation can also cause leaks.

Blocked Pressure Valve

Water heaters create a lot of pressure, so they have a pressure valve that releases steam. Sediment and debris can block this valve, causing the water temperature to spike. Too much pressure can damage the hot water tank and cause it to rupture. The most common sign of a blocked pressure valve is boiling water. If you open the tank and see boiling water, turn your heater off immediately and call a professional to fix the problem. A pressurized water heater can leak and become an explosive hazard.

Faulty Heating Element

Faulty heating elements are a problem specific to electric heaters. If a heating element malfunctions, it may stay on all the time and continually heat water. If you don’t replace a faulty heating element, it can burn out, and you won’t have any hot water until you replace it.

How to Prevent Water Heater Overheating

Most overheating is a result of blocked or clogged components. One way to keep your water heater in top condition is to clean and flush it regularly. Flushing your tank removes sediment, debris, rust, and other materials that can cover your heating elements and thermostat sensor. Cleaning your water heater will also remove clogs that can damage the pressure valve. Experts recommend you clean your water heater at least once every 6-12 months. If you live in a place with high mineral content in the water, you may need to flush it more frequently. High mineral content can also cause leaks, so there are multiple reasons to flush your system regularly. Check out our articles to learn why your water heating is leaking.

How to Replace a Broken Thermostat

Usually, the most common water heater issue is a broken thermostat. You can often replace this component on your own.

1. Locate the Thermostat

First, you need to turn the power off and locate the thermostat. Most water heaters have an external panel with a thermostat underneath. You may need a screwdriver to remove the panel.

2. Test the Power

Once you have found the thermostat, test the wires and terminals with a non-contact voltage tester. If the reader shows no voltage, then it’s safe to touch the thermostat and wires. If you get a voltage reading, double-check that you shut off power to the heater.

3. Remove the Thermostat

First, take a picture of the wiring so you can reassemble it later. Start removing the wires and terminals, then remove the thermostat from its compartment. Place the new thermostat, taking care not to bend the mount clips. Connect the wires and terminals and screw the panel back in.

4. Test Your Heater

Once you’ve installed the new thermostat, test the water heater to make sure it’s working. Open your faucets to see if it’s at the correct temperature. You may need to wait a few hours for the water in the tank to heat up. 

Do I Need to Replace My Water Heater?

It depends on the nature of the problem. You can usually replace a broken thermostat, and you can clear sediment from the bottom of the tank. However, some issues will require replacement. If your pressure valve or gas valve fails, you may need to replace the entire heater. High pressures can also damage the integrity of the tank.

Contact Core Plumbing Today!

An overheating water heater can lead to costly repairs. That is why you should call water heater repair experts in San Diego. Our expert technicians at Core Plumbing can diagnose any water heater overheating issues. Contact us online or call us today at (858) 293-4110 to schedule an appointment!