Troubleshooting Your Heater's Thermostat

Posted on: 1 April 2021

A long, cold season can be tough on even the best heaters, so reaching warmer seasons provides a nice break — and a great time to check out any issues that seemed to pop up toward the end of the cold weather. Thermostats are usually one of the more durable parts of a heater, so when they start to act up, it can be more than annoying. Most of the time, a problem with the thermostat is simple to fix, but it can indicate that something is wrong systemically.

If It's Digital, Check the Battery and Contacts

First, if you have a digital thermostat, change the batteries. Most digital thermostats will give you a low-battery message, but even if you haven't seen that message, put in fresh batteries just to check that possibility off your list. You'll remove the uncertainty about whether or not the batteries are to blame for any malfunctions. Changing the batteries will also allow you to look at the contacts (the terminals) to see if there's any battery corrosion. If there is, a cotton swab dampened with a little vinegar or lemon juice will help you remove the corrosion and improve the contact.

If It's Not Digital and Not Working at All, Check the Breaker Box

If the thermostat isn't digital and doesn't seem to be working at all, look at the breaker box and find your heater's circuit breaker. Even gas heaters can have electrical connections for things like the thermostat. Make sure the breaker switch is in the position that indicates it's on. It's possible you may have tripped the circuit, resulting in the thermostat not working because now there's no power reaching it.

If It's Programmable and Working but Changing the Temperature on Its Own, Check the Settings

If the thermostat is programmable and the batteries are fresh, check the programmed settings, even if you don't typically rely on the programming. Sometimes a thermostat will default to a pre-programmed setting, even a factory-programmed one, if you don't follow the correct steps to change the temperature. For example, some thermostats have a "hold" button that you need to press when adjusting the temperature. If you don't press that "hold" button, then the thermostat will default to a pre-programmed setting after a certain amount of time. Change the programmed setting to one that matches the temperatures you prefer the thermostat to be at.

Did You Turn It off and Then on Again?

Thermostats are like any electrical item: Sometimes turning them off and then back on at the breaker is necessary to reset the thermostat (you can't really unplug them, so you have to go to the breaker box). Turn off the thermostat and heater, flip the breaker switch that goes with your thermostat so that it's off for several seconds, and then turn it back on.

If none of these work, then you have to consider the possibility of bad wiring or a problem further along in the heating system. That's when you need to call a heating repair service, as this is one appliance where you don't want to mess with the wiring or elements on your own.