The thermostat is essentially the brain of an HVAC system as it controls the system and signals it when it needs to turn on and off. That means that any issues with your thermostat will usually either prevent your heating from working as it should or make it so that your heating never turns on. Learn about some of the most common thermostat issues you may encounter over the winter along with what can cause them and what you may be able to do to fix them. That way, you should easily be able to tell whether it’s something you need to hire a professional for or not.
Screen Is Blank
One issue you may occasionally encounter is the screen on your thermostat shutting off. If your thermostat is fairly old, this issue can indicate that the thermostat is just dead. Another possibility is that a recent power surge fried the electronics in the thermostat. In either of these cases, the only thing you can do is have a technician replace the thermostat. A failed thermostat during winter is generally an emergency situation since you’ll have no way to run your heating until you can get a new one installed.
While it’s possible that your thermostat is dead, this issue more commonly happens due to the thermostat not having power. Some programmable thermostats run solely on battery power. Others receive power from the HVAC system but also have batteries that act as a backup so the programmed settings don’t get reset when the power is out or the circuit breaker gets tripped. It’s not always easy to tell which is the case without looking the model up. As such, you should just go ahead and replace the batteries to see if this gets your thermostat to come back on.
If your thermostat doesn’t have batteries or replacing the batteries didn’t fix the issue, the next thing to check is that the circuit breaker for your HVAC system is still on. While it doesn’t happen that often, it’s possible that the blower for your furnace or one of the motors in your heat pump system drew too much power. This can lead to the circuit the system is on getting overloaded and causing the breaker to trip. If you see that the breaker did trip, resetting it will restore power to the thermostat so it turns back on. If everything then works fine, you may not have anything to worry about. If the breaker trips again at any point, you need to get your HVAC system inspected as it likely has some type of electrical problem or a motor that’s failing.
If the breaker is still on, there’s a good chance your thermostat isn’t receiving power due to a wiring issue like a loose electrical connection. This sort of problem is more common than you may think, especially with older thermostats, and will require a professional to fix.
Not Reading the Temperature Correctly
Another somewhat common issue is that a thermostat will stop reading the temperature in the house correctly. This can result in the house frequently being too cold due to the heating not running as often as it should or shutting off too soon. It can also cause your home to be too hot due to the heating system running more often or longer than necessary.
You can easily check whether your thermostat is registering the right temperature by using a kitchen thermometer. If you have an instant-read thermometer, you just need to hold the probe near the thermostat for a few seconds to see what temperature it registers. If you only have a manual meat or candy thermometer, you’ll need to tape it on the wall just next to the thermostat and wait a few minutes to see what temperature it shows. However, you need to make sure to put a rag or a few paper towels between the thermometer and the wall. If not, the thermometer will read the temperature of the wall and not the air and not produce an accurate reading.
There may be a difference of 1-2 degrees between what the thermometer reads and what your thermostat shows. Anything more than this indicates the thermostat isn’t accurately reading the temperature. One of the most common reasons this happens is that the internal sensor in the thermostat is coated in a layer of dust. Dust can essentially act like insulation and block air from reaching the sensor, causing the thermostat to produce an inaccurate reading. This is something you can sometimes fix just by taking the cover off the thermostat and then using a can of compressed air to blow everything out.
The location of the thermostat can also result in it often or never producing an accurate reading. For instance, if the thermostat is on an exterior wall or near a window or exterior door, it will often register a lower temperature than what the house actually is. Similarly, if the thermostat is in an area where it gets hit by sunlight, it will register a higher temperature whenever the sun is shining on it. In either case, the only way to get the thermostat to always register the correct temperature is to have a technician move it to a different location.
If your thermostat seems to be in a good location and cleaning it out didn’t fix the problem, you’ll need to get it inspected. In most cases, this issue indicates the thermostat is giving out and can’t work accurately anymore. It can also just mean your thermostat isn’t calibrated correctly and you need to have a technician recalibrate it.
Repeated Clicking Noises
You’ll usually hear your thermostat click once when it signals your heating to turn on and then click again when it tells the heating to turn off. This clicking is the sound of the thermostat’s relay switch activating and sending a signal to the HVAC system’s control board. You may also encounter a situation where the thermostat repeatedly clicks when your heating is off or while it’s running. This most commonly happens because the batteries are almost dead. It can also be a sign that the thermostat is failing and you need to replace it.
If your thermostat keeps clicking while your heating is off, it means it’s trying but failing to signal your HVAC system to turn on. This can happen because there’s an issue with the wire that connects the thermostat to the control board that’s preventing the signal from reaching the board. It can also happen because the control board is malfunctioning or has failed and can’t turn the heating system on. One final possibility is that there’s some other electrical issue with the heating system that’s preventing it from coming on. The only way to diagnose the root of the problem is for a technician to perform an inspection. They’ll usually start by testing the thermostat and checking its wiring. If the thermostat is working properly, they’ll then move on to testing the control board and checking the rest of your heating system’s wiring.
Since 1993, Southern Pride Service has been providing trustworthy HVAC services to residential and commercial customers in White Plains, MD, and the surrounding areas. Our experienced technicians can help if you’re experiencing any issues with your thermostat. We’re also the company to turn to if you want to save on your energy bills by upgrading to a smart thermostat. To schedule an inspection or any other heating or cooling service, contact us today.
