Thermostat Not Working? 13 Reasons Why & Troubleshooting Tips

Thermostats play an essential role in regulating home climate. They communicate your preferred settings to your HVAC system, keeping your home as warm or cold as you need it to be.

Unfortunately, like any other device, thermostats can malfunction, affecting your comfortable home environment. The good news is that most of the issues require simple fixes that you can even do on your own.

Let’s look at 13 reasons why your thermostat is not working and what you can do to resolve the problem.

1. Incorrect Thermostat Placement

As your thermostat reads the ambient home temperature, its placement plays a crucial role.

If you have it installed in a kitchen, you are unlikely to get the correct reading since other electrical devices such as the oven and toaster also generate heat. As a result, your thermostat will sense that your house is quite hot when in reality, it’s just your kitchen.

The ideal thermostat placement is the center of your home or a room you frequently use. Also, you should install it on an interior wall as it is not directly in contact with the fluctuating outdoor environment.

If you are living in a two-story building, it is recommended to install your thermostat on the first floor. The main reason for this is because the second floor often gets warmer due to hot rising air. A better solution, however, would be to install a dual-zone thermostat.

Read this article for detailed two-story house air conditioning tips.

Another tip is to avoid installing your thermostat under direct sunlight or near vents, as this will result in ghost readings. An empty hallway is also a big no as it’s a narrow place with little air circulation. You must also keep your thermostat away from heat-generating appliances such as ovens and lamps as temperature sensors in your thermostat will read it as ambient home temperature.

2. Lack of Thermostat Maintenance

Regular cleaning of your thermostat is as important as your HVAC system’s maintenance. Your thermostat can cause frequent short cycling of your cooling/heating equipment if not properly maintained. This results in your home temperature never actually reaching your preferred settings.

Dust and debris can build up inside the delicate thermostat components, triggering electrical and mechanical issues. Dirt particles can also block the sensors leading to incorrect temperature readings.

To clean the device, turn it off and remove the cover. Some thermostats have a cover that can be removed while it’s mounted by unscrewing the nuts on the side or bottom. Others have to be removed from the wall.

Take a microfiber cloth or a soft brush and wipe the debris gently. You can also use a compressed air duster if you have prior cleaning experience, as it can dislodge delicate parts. Also, make sure you don’t use a wet cloth or wipes to clean the thermostat as it can damage the internal components.

3. Malfunctioning Sensors

A thermostat relies on its sensors to give the correct readings. If you notice your thermostat is displaying inaccurate readings or your HVAC unit is struggling to maintain your desired settings, it is likely a sensor issue.

You can also manually check for malfunctioning thermostats by comparing your thermostat readings with a room thermostat. If you notice a difference, then contact an HVAC professional. Fixing the sensors is usually a tricky job, and, in most situations, the thermostat has to be replaced.

4. Thermostat is On Auto Mode

Some thermostats do not allow manual temperature changes if set on auto-mode. When your thermostat is not picking up the commands you’re giving, don’t just panic yet!

Change the mode from auto to heat or cool to change the settings manually.

5. Incorrect Calibration

If you notice that your thermostat is not correctly sensing your home temperature, it might be due to calibration loss. This can occur due to debris accumulation inside the thermostat, something accidentally bumping into the device, or power loss.

Before making the correction, verify that it’s a calibration issue. Take a simple household thermometer and place it inside the room where your thermostat is installed. Keep it as close to the thermostat as possible to avoid temperature fluctuations. Wait at least 15 minutes before checking for a difference between the two readings. The greater temperature difference indicates calibration loss.

Calculate the difference between the thermostat and thermometer readings. For example, if your thermometer is reading 68F and the thermostat is reading 73F, your thermostat is reading 5 degrees higher.

Every thermostat has different controls and calibration, so refer to the manual for assistance. You enter the calibration mode on some models by turning the thermostat off and pressing the up and down buttons simultaneously. When a number displays on the screen, press the arrow keys to adjust the temperature change. Then exit the calibration menu.

Recheck the calibration with a thermometer following the same procedure. Continue your adjustments till you get the correct reading.

6. Old Thermostat

Like any other appliance, thermostats have a lifespan and need to be replaced after that period. While all devices are different and the lifespan varies depending on various factors, the average life expectancy of thermostats is ten years.

An outdated thermostat will have trouble sensing the correct temperature making it difficult to maintain a perfect home environment. Besides, incorrect reading forces your unit to work harder, resulting in energy wastage.

When going for a replacement, consider going for a smart thermostat for more hands-off control and long-term energy savings. The best part is that you don’t have to fiddle around with the settings every now and then, and your home stays at the perfect temperature at all times. Plus, a smart thermostat can save you money in addition to helping you automate home climate.

Here’s a handy guide on different types of thermostats and which one would best suit your home.

7. Thermostat is Locked

Digital thermostats have a lock or range control feature to prevent others from making any unnecessary temperature changes.

However, sometimes you can forget that you turned this mode on and start panicking that your climate control gadget has failed. If something like this happens, always check your thermostat settings before doing anything else. Turning off this feature will solve the problem.

8. Loose Wiring

Over time, your thermostat can corrode, and the wiring can come loose. This can interfere with electrical connections, and as a result, your thermostat’s communication with the HVAC unit is lost.

To troubleshoot this problem, turn off the power at the circuit breaker. Take off the cover and check that the wires aren’t corroded or detached. If you find corrosion, use a wire stripper to remove that section. Reveal a new section on the wire and then reinstall it in the terminal. Also, tighten any loose screws if needed.

Note: Never remove the thermostat cover before turning off the power at the breaker, as electrical components can pose a safety hazard. Plus, you should only take the DIY approach if you are absolutely sure you can handle the electrical connections. If you are doubtful, call an HVAC technician.

9. Power Issue

If your thermostat’s screen is completely blank or fading out, there might be a power or an electrical connection issue. Dead batteries, tripped circuit breaker, and blown-out fuse can cause your thermostat to stop working.

Before checking anything else, make sure that the power switch is on. If this doesn’t work, turn off your thermostat and inspect the batteries; replace if needed.

10. Batteries Have Run Out

When batteries run out in a battery-operated thermostat, it will shut down, and you will see a black display. Screen fading or flickering also indicates loss of battery power.

Replacing the batteries is a simple solution, and you will have your thermostat working effectively in no time. Refer to your user manual to see how to remove the dead batteries and add new ones.

11. Thermostat Isn’t Levelled

Tried all the hacks, but still, your thermostat isn’t working?

While most newer thermostats use some form of an electrical temperature sensor, older thermostats use mercury or magnetic switch. With a mercury switch, as the temperature in the room changes, the coil expands or contracts. For this to work as intended, it requires proper leveling on the wall. If your thermostat is slightly tilted, it affects the reading accuracy.

To fix this problem, remove the thermostat from its place and use a level to ensure the correct position on the wall.

12. Tripped Circuit Breaker

When the circuit breaker trips, your thermostat will shut down, and you will notice a blank screen.

A circuit breaker is a safety component that protects appliances when the circuit overloads or short circuits. A power surge or some fault inside your unit can cause this issue. A faulty circuit breaker can also trip.

Inspect your circuit breaker and if it has tripped, simply flip the switch back on and check if this restores the thermostat screen. If it keeps tripping repeatedly, do not try to reset it as it can result in a fire. Instead, turn off your HVAC system and your thermostat and seek professional help immediately.

Here’s what to do if your air conditioner circuit breaker keeps tripping repeatedly.

13. Thermostat Isn’t Compatible with Your HVAC

You have just purchased the latest smart thermostat model, but it’s not working with your system. Chances are your thermostat is having compatibility issues.

Check your thermostat’s compatibility with your HVAC unit. You are likely to find it on the company’s website, or you can contact their support team for information. When purchasing a new thermostat, do check the requirements beforehand.

The Bottom Line

Incorrect placement, lack of maintenance, and loss of calibration are some of the common issues that can prevent your thermostat from working effectively. Sometimes, there is no apparent reason for malfunction; your thermostat may have completed its lifespan and need to be replaced. When purchasing a new thermostat, it’s recommended to upgrade to a more efficient model. If you can’t figure out why your thermostat isn’t working, it’s always best to call in the professionals who have the expertise to fix your device.

Originally published at https://www.cielowigle.com on February 18, 2022.