June 1, 2020

As the main way of controlling your entire HVAC system, the thermostat plays an important role in managing your indoor air quality. A malfunctioning thermostat can keep your AC from running or cause wear and tear by making your system turn off constantly. Fortunately, many thermostat problems are actually quite easy to fix. Here are some basic thermostat troubleshooting tips that any homeowner can try when their HVAC system isn’t working correctly.

Check to See What Your Thermostat’s Actual Settings Are

This might seem obvious, but one of the first things you should do is look at your thermostat’s settings. It is possible that your system might not be turning on because the switch for “heat” got bumped to “cool” instead. Or your air conditioner might be running nonstop because your thermostat somehow got set to 60 degrees. Always make sure your thermostat is actually turned to the right setting before proceeding with other troubleshooting tips.

Make Sure the Thermostat Is Powered

If your thermostat’s digital display is not visible, then you are most likely dealing with some sort of power problem. Look on your circuit panel to see if any breakers are tripped. You can also open the thermostat cover to replace the batteries if necessary.

Many modern thermostats are powered by wiring inside the wall. You can check to see if any wire contacts are loose by removing the thermostat and examining the wiring. You should also make sure that no wires are touching since this can make the HVAC run nonstop. Just remember that any loose wiring can pose a shock risk. Therefore, you should always turn off the breaker to the area.

Another potential thing to check is the fuse inside the thermostat. If it is blown out or separated, you may need to replace the fuse. If you fix power issues but they come back later, you might be dealing with an electrical problem. Things like old wiring or mismatched voltages can cause repeated power issues with a thermostat, so you may need a technician to check out your thermostat.

Ensure Your Thermostat Is Compatible With Your HVAC System

If you have recently installed the thermostat or a new HVAC system, the underlying issue might be a compatibility problem. This is especially common if you have a newer and less common HVAC system, like a variable-speed AC or a heat pump. Older styles of thermostats may not be able to handle these new inputs. To see if your thermostat can work with your HVAC system, carefully read the user manual for each product. If they are not compatible, you may just need to upgrade your thermostat.

Look at Your Heating and Cooling Relays

To switch your HVAC system on and off, a thermostat uses relay switches to direct power currents to your heater and air conditioner. These connections can get loose, or the relay contacts can get too hot and sticky. If a relay is not switching between open and closed positions properly, your system may not turn on at all. Another potential problem is that your thermostat might refuse to shut off your system altogether.

If you suspect this is the problem, turn off the breaker to your HVAC system and thermostat, then take a look at the relay wires. Pull on them gently to see if they are snugly connected. In some cases, you can fix the problem yourself by tightening connections. However, a faulty relay switch is not something you can handle yourself. If all the wires are connected snugly but the relays still are not working, you need to call in an expert.

Test to See If Heat or AC Is the Problem

Sometimes, it might seem if your thermostat is acting up when the problem is actually your heat or air conditioning system. Since most thermostats are meant to handle both of these systems, you can try out some different settings to identify the issue. Try testing your thermostat on various modes, including heat, cool, fan, and auto. If it is only broken for one of these settings, the problem might be your unit itself, not the thermostat.

Clean Your Thermostat

Just like any other part of your HVAC system, dust and debris can build up on your thermostat and keep it from working. The most common way that dirt breaks a thermostat is by building up on the temperature sensors. This can make your system incorrectly read the room temperature, running at unnecessary times or not kicking on when needed.

Cleaning your thermostat is fairly simple. You just need to remove it from the wall and use a soft brush or microfiber cloth to remove dust. Follow the manufacturer’s instructions for cleaning the interior too. Pay special attention to the metal coils and contact plates, since debris in these spots can keep the thermostat from running.

Consider Your Thermostat Position

In some cases, the problem actually has nothing to do with the thermostat itself. Instead, it could just be positioned in the wrong spot. Your thermostat regulates your home’s HVAC system by constantly checking the temperature. Being in an area that does not accurately reflect your home’s temperature can lead to a system that runs too much or not enough. Check to make sure your thermostat is not located near direct sunlight, stoves, refrigerators, vents, or windows that could be making it read a wrong temperature.

Another potential problem can be an unlevel thermostat. Older models may use a mercury switch to run your HVAC, and if the model gets tipped, it can be reading temperatures incorrectly. To change a thermostat’s position, you’ll usually need to get help from the professionals. However, just knowing what the problem is can still make it a lot easier to get help.

Adjust Programmable Settings

Especially if you have a newer “smart” thermostat, there can be all sorts of programs and settings that change how a thermostat functions. If your thermostat is turning on at random times or changing its desired temperature randomly, the problem is most likely in your settings. Your thermostat might be automatically adjusting settings on its own until you disable those automatic options, or you might’ve accidentally set up a weird program yourself.

The exact steps for adjusting settings will vary quite a lot depending on which thermostat you have. Some thermostats may require you to download an app while others may have a certain code you have to punch in with the buttons. Therefore, your best option may be going to the manufacturer’s website to get instructions for your specific model. If you cannot figure out how to change the thermostat program, consider restarting it altogether. This can erase any accidental inputs and return it to its original state.

Many thermostat problems can be solved at home, but if these tips still cannot fix your problem, call in the professionals! McGowan’s Heating & Air Conditioning has plenty of experience handling malfunctioning thermostats. We can also help out with other sorts of installations, repairs, and maintenance on heating and air conditioning systems in your Jacksonville, FL, home. Make an appointment with our experts by giving us a call now.

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