Common Causes of an AC Running Constantly If your AC cooling cycles last more than 30 minutes or run all day, you likely have one of the following common AC problems: Thermostat fault. Dirty or clogged air filter. Low refrigerant.
This is the answer - there is an ``allow overcool'' setting that will continue to run your A/C to help with humidity. It needs to be turned off if you don't want this to happen.
If your air conditioning system won't turn off, there are most likely malfunctioning mechanisms, such as a faulty thermostat or fan limit switch, frozen evaporator coils, electrical issues, or incorrect thermostat or fan speed settings.
Under normal conditions, an air conditioner running in a properly sized system should cycle for about 15-20 minutes before shutting off. This length of time allows it to cool the air effectively, reach the desired temperature, and then turn off to save energy.
It could (likely) be one of two things. Either the thermostat is sticking and not disengaging or you have a short in the wiring.
The short answer is your furnace won't turn off due to some kind of error or malfunction within your furnace, thermostat, or HVAC system. It could be the wrong thermostat setting is being used, a clogged air filter or your thermostat itself is no longer working properly.
If the temperature is set to 74°F but the thermometer shows 78°F, you will have to recalibrate the thermostat to account for this 4-degree deviation. Even with older AC units or furnaces, you might have to recalibrate your thermostat from time to time.
Your air conditioning system works in cycles: it runs for about 15 minutes at a time until it reaches the appropriate temperature, turns off for about 10 minutes, and then turns on again. Problems with your system, however, can cause it to stay running for longer periods of time or indefinitely.
Here's the thing: It's normal for your AC to run continuously during hot summer months. You see, on extremely hot days—we're talkin' high 90s to 100s—your system needs to keep up with the incoming heat. To do that, it will run longer in order to maintain a constant, desired temperature in your home.
If your AC won't turn off, it could be due to thermostat malfunctions, electrical component issues, dirty or clogged components, or an incorrectly sized system, which can increase energy bills and reduce system efficiency.
Air conditioners don't defy time; they follow a cycle that's affected by more than just a glance at the thermostat. Typically, it takes about an hour for an average-sized air conditioning unit in typical conditions to lower room temperature by one degree Fahrenheit.
You could have a dirty air filter, clogged condenser coils, frozen evaporator coils, a broken relay switch, or a bad thermostat, amongst other common air conditioner issues.
If the AC unit or furnace constantly runs and doesn't turn off when the desired temperature is reached, the wiring within the thermostat may be failing. It can also be a sign of miscalibration, which causes the thermostat to send the incorrect signals to the air conditioner, furnace, or heat pump.
How Often Do I Need to Change Out My Air Filter? Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.
Check the Thermostat
Your thermostat controls your furnace and basically tells the unit when to turn on and off. It's often to blame when your furnace won't stop running. Sometimes having the heat turn off is as easy as adjusting an incorrect thermostat setting. Make Sure Your Thermostat is Set to “Auto”.
Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it. For those wondering specifically how to reset air conditioner thermostat models, the process is generally the same.
When things are working right, your central air conditioner should run for 15 to 20 minutes and then turn off for a few minutes. It will do this two or three times every hour. It may run longer when it's sweltering outside.
If your AC unit is experiencing electrical problems, it can cause the system to run continuously, even after reaching the desired temperature. Faulty wiring or a malfunctioning thermostat system fan can be the culprits.
An undersized air conditioning system most commonly manifests as an air conditioner that never stops running. When this occurs, cooling coil pressure will start to drop before freezing over, which could damage your AC's compressor.
There are a number of reasons why your air conditioner might be running but not cooling. It could be an issue with the thermostat, the compressor, or the evaporator coils. Or, it could simply be clogged with dust and debris, which is preventing it from working properly.
For many of us, 70 degrees is the ideal indoor temperature, but when it is close to 100 degrees outside, your AC unit will be working quite hard to meet these expectations. Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits.
Some of the most common thermostat issues include:
The thermostat is broken, not properly level, or dusty. The thermostat needs to be recalibrated. There is loose wiring causing a thermostat issue.
Key Takeaways. Your AC might not cool properly due to thermostat issues, an undersized unit, or extremely high outdoor temps—so check those first. Keep an eye on airflow—replace clogged filters every 3 months, and make sure vents and ducts aren't blocked for efficient cooling.