How Do You Know If Your Water Heater's Thermostat Is Faulty?

A standard storage-tank water heater is a relatively simple appliance that typically only includes a few components. These units are fairly robust, making major problems somewhat rare, especially in water heaters that aren't approaching the end of their usable lifespans. However, there are a few common issues that you may face, including faulty thermostats.

Your water heater must maintain a relatively precise temperature: warm enough to prevent bacterial growth and to deliver hot water throughout your home but not so warm that it poses a scalding hazard. The thermostat is the component that keeps the water heater's temperature within this range. As a result, a failing thermostat can produce numerous and even potentially dangerous symptoms.

How Does Your Water Heater's Thermostat Work?

Thermostat designs can vary slightly between water heaters. For gas-fired heaters, you'll usually find the thermostat relatively close to the burner, where it can measure the water temperature at the bottom of the tank. Since the water near the bottom is cooler, this design provides a more reliable and consistent reading that generally prevents the heater from rapidly cycling.

Like furnaces, most gas-fired water heaters use a single-stage burner. The thermostat controls this burner by igniting it when the water temperature falls below a user-controlled setpoint and extinguishing the flame once the water reaches an appropriate temperature. Higher-efficiency units may use burners with multiple stages or modulating burners that can more closely match heating needs.

How Do You Know If Your Water Heater's Thermostat Is Faulty?

A faulty thermostat will impact your water heater's ability to maintain an appropriate temperature, which can lead to numerous symptoms. These symptoms include:

  • Water that's much too hot
  • Water that's much too cold
  • Inconsistent water temperature
  • Inability to alter water temperature
  • Frequent burner cycling

If you suspect your water heater's thermostat may be to blame for problems with your hot water, a good first test is to adjust the setpoint slightly up or down. However, make sure you keep it within a safe range. You can use a thermometer to test the water at your faucets. If you don't notice any change in water temperature as you adjust the setpoint, the thermostat may be to blame.

How Can You Fix a Faulty Thermostat?

Fortunately, replacing a water heater with a faulty thermostat is almost never necessary. Still, you'll want to contact a professional to perform a more in-depth diagnosis, even if you're relatively sure the thermostat is to blame. Other problems may produce similar symptoms to a faulty thermostat, so it's important to have an expert rule out these possibilities.

Once they confirm the problem, a professional should be able to fix or replace your thermostat relatively easily. As long as your water heater is in otherwise good condition, your new thermostat should provide you with years of reliable hot water.

For more information, contact a company such as American Services.