If your hot water isn't working, it can cause quite a stir. Most manuals will tell you to 'check the thermostat,' but to the average Joe, this can be quite tricky. An electric water heater comes with two thermostats; both control different heating elements. How exactly do you check to see if they’re working?
If you need to check your thermostat, you’re in the right place. Follow this guide for a step-by-step on how to test a water heater thermostat, and get your hot water flowing again.
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Common Reasons For Testing Thermostats In Hot Water Heaters
The thermostats are located on the side of the water heater. They’re responsible for controlling the temperature of the water, making sure it reaches 120F. There’s also a high limit switch, which will be triggered if the temperature goes over 170F.
The thermostats control the heating elements inside of the tank; the upper thermostat controls the lower. The switch is shut when the water needs to heat, and vice versa. If you’re not getting hot water, there could be several reasons:
How To Test A Water Heater Thermostat With A Multimeter
This is the guide on how to test electric water heater thermostat with multimeter. To test your water heaters thermostats, you’ll need two tools: a flathead screwdriver and multimeter.
The multimeter will read your thermostats with ohms (Ω) of resistance; this is how much current is flowing through the opposition, such as insulators. All materials will resist a current somewhat.
It’s also very important to turn off the power supply to the water heater. Failing to do so can cause a serious hazard to you.
Can You Test A Water Heater Thermostat Without A Multimeter?
It is not recommended to test the thermostat of a water heater without a multimeter. You should not test the electric currents with anything other than a multimeter, as this can be a serious hazard. There is a simple test you can do without checking any of the electrics.
Run one of your hot water faucets, and get a feel of the temperature. You can do this with your hands or with a thermometer if you so choose.
In both of these circumstances, if you don’t own a multimeter, it’s best to call in a professional to help determine the cause of the problem. If you’re ever unsure, you’re always better off having someone take a look at it.
Testing the Thermostat Of Popular Water Heater Models
A.O. Smith Water Heaters
A.O. Smith recommends turning off all electricity supply to the heaters and removing the power wires. The steps on testing remain the same, but you will find the terminals on the bottom of the thermostat rather than on the sides. The terminals will need to be unscrewed a little to access the wires.
Rheem Water Heaters
You should follow the instructions above as directed, and follow any necessary precautions to avoid injury or death. Before checking the terminals on the thermostat, Rheem recommends checking there isn’t a malfunctioning reset button that could be causing your heater to trip. If you’re satisfied that it’s not that, you should follow the instructions above.
Atwood Water Heaters
There are two different thermostats attached to an Atwood model. One is labeled 'T’Stat,’ which is the propane gas control. The second is E.C.O., which stands for ‘Emergency Cut Off,’ which turns off the heater when the water is too hot. To test both, you will find the heating element terminals and power lines underneath each label, and you can easily test both with the multimeter.
Suburban RV Water Heaters
The thermostats on a Suburban model are next to each other, enclosed in a plastic cover. While removing the wires, you should make sure you know where each one goes, as cross wiring can be dangerous. The terminals are easily accessible under the casing and can be tested with a multimeter using the instructions above.
People Also Ask (FAQs)
How long do water heater thermostats last?
You can expect approximately 8 - 12 years of use from your thermostats before they will need replacing. If you notice any issues with its use during this time, it’s best to test it or call a professional.
What happens if the water heater thermostat goes bad?
The lower heater thermostat is controlled by the upper, so if the upper one is malfunctioning, the lower will never switch on. You’ll be able to tell this if there’s no hot water. If the lower thermostat is not working correctly, the hot water will go cold quickly.
What are some reliable thermostat brands to buy?
A.O. Smith is one of the first companies to be mentioned in regards to water heaters. Their company is reliable and will provide solid working water heaters. Rheem is also reliable, producing high-quality and innovative water heater thermostats. Bosch is the forefront in technology and produces tankless water heaters that are efficient.
Losing your hot water is infuriating, and now with the tools to test your thermostats yourself, you can determine the issues with your tank and whether it’s simply the case of a power surge or something more serious. You should always take necessary precautions when testing, and if you're ever unsure, or it doesn't look safe, there is no shame in calling a professional. Good luck!