If your AC is running but not cooling, it could be due to a dirty air filter, incorrect thermostat settings, a malfunctioning thermostat, a refrigerant leak, dirty condenser coils, blocked vents or ducts, a faulty compressor, frozen evaporator coils, or electrical issues.
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.
One possible reason your AC is not reaching the set temperature is that the thermostat could be dirty. If dirt, dust, or other debris has accumulated within the thermostat box, it can cause the wires to heat up or other issues. Thermostats are cleaned during routine HVAC maintenance to help prevent this from happening.
Check the power supply, try turning the thermostat on a few times - if the screen is still blank, try the following tips to diagnose the problem. Have you considered that your thermostat is running on batteries that may be dead? That is the next completely harmless cause of the dead display.
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.
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.
If your thermostat is blank, the first thing you should do is check the batteries. Chances are, the batteries have died and the thermostat simply can't power on. Replace the batteries and see if your thermostat turns on.
If your AC shows irregular temperatures, where sometimes it's much cooler than other times, this can indicate AC sensor malfunction. This, in turn, will lead to AC sensors needing replacement.
If your AC isn't lowering the temperature, have your HVAC technician check the refrigerant charge. There's a good chance it's off.
Cooling a house from 80 to 72 degrees is a common goal for many, especially during the peak of summer. On average, this process takes roughly two and a half to three and a half hours.
A bad thermostat can be detected when your AC or furnace is not turning on, your HVAC systems are not turning off, the thermostat not responding, your HVAC system is short-cycling, the room temperature not matching the temperature displayed on the thermostat, and the programmed setting resetting themselves.
Clean your Air Filters, Vents, and Ducts – A clogged air filter will struggle to meet the thermostat's set temperature since the dirt and debris buildup prevents air from circulating through the vents. And as airflow into living spaces drops, so do comfort levels.
Turning off your AC when it's not cooling is more than a precaution; it's a necessary first step in troubleshooting and protecting your system from further damage. By understanding when to perform simple checks and when to call in the experts, you ensure your air conditioner remains a reliable refuge from the heat.
Power down your AC: Turn off your AC unit and unplug it from the power source. This will ensure that you stay safe while working on the unit. Locate the reset button: Most air conditioning units have a reset button located near the outside unit. It is usually a small button located inside a small hole.
If your AC is running but not cooling, it could be due to a dirty air filter, incorrect thermostat settings, a malfunctioning thermostat, a refrigerant leak, dirty condenser coils, blocked vents or ducts, a faulty compressor, frozen evaporator coils, or electrical issues.
Shut off your system by hitting the isolation switch, wait 30 to 60 minutes and then turn it back on. This manual reboot fully disconnects your AC unit from power, allowing all electrical components to reset.
As simple as it sounds, a dirty thermostat could be why the thermostat room temperature and setting do not match. Gently cleaning the thermostat interior with a clean, soft paintbrush is the best way to avoid further damage.
The thermostat is blank but the fan works, what does that mean? If the display is not working but the fan is on and your thermostat is in the “auto” position, this is because the display controls the heating and the AC but in the “auto” position, the fan can automatically come on and off.
Many factors can cause this issue, including clogged filters, refrigerant leaks and the wrong unit size. While it's possible to troubleshoot it yourself, it is best to contact an HVAC professional for your AC problems.
First, check your filters and coils for dirt and debris that may be impeding airflow. Once you've cleaned the filters and coils, run the air conditioner with just the fan so that the ice accumulation can melt off. If the AC still doesn't blow cold air, it could be that refrigerant levels are too low.