Why is My AC Not Working After Changing the Thermostat?Here at Edge Heating & Air, we encourage our customers to consider installing a smart thermostat because they’re just that much better than programmable thermostats. Perhaps we even inspired you to try installing one yourself. Unfortunately, this sometimes leaves folks asking, “Why is my AC not working after changing the thermostat?” This can be due to a number of issues, and this article is designed to help you find the solution to your troubles.

In the following article, we’ll explore just some of the reasons your AC is not working after changing the thermostat.

1. It could be a simple issue with your settings.

Before doing anything too rash, like taking apart your new thermostat, the first thing you’ll want to double-check is your thermostat settings. In many cases, thermostats won’t properly communicate with their air conditioning systems because of a simple error in the thermostat settings.

First, make sure that your thermostat is set to “cool” and not “heat.” If your settings aren’t on “cool,” your AC won’t kick on. If that looks good, the next thing to consider is if your fan is set to “ON.” Instead, it should be set to “AUTO.” 

If that doesn’t do the trick, you might consider trying to set your thermostat five degrees higher than normal. This can push your AC to kick on. If it turns on, there may be a setting that’s telling your air conditioner not to turn on until it reaches a higher temperature. 

2. Something went wrong during installation. 

Now that you’ve checked your thermostat settings, it’s time to consider that your new thermostat may not be turning on your AC due to improper installation. While YouTube has many great tutorials on how to install pretty much every type of thermostat out there these days, installing anything for the first time can be a challenge.

If you suspect that something went wrong during installation, a good place to start is by working backward through each step you took. Take out the instruction manual you followed, and double-check if your thermostat was installed properly.

3. There’s no or little power for the thermostat.

Sometimes, installation isn’t necessarily the issue. Another significant aspect of ensuring that your thermostat is able to adequately communicate with your air conditioner is checking the power supply. First, you may want to check the wiring itself to ensure that everything appears to be connected.

Once you have done that, double-check that your thermostat has a fresh set of batteries, if applicable. If batteries aren’t the issue, you may also want to check if the electrical supply that connects to your thermostat is in working order. If you suspect significant issues with your electrical system, you may want to consider contacting an electrician. 

4. There are loose or corroded wires.

When you’re pretty sure that your power supply isn’t the problem, you may want to take a closer look at the wiring connected to your thermostat. If the wiring is not properly connected, loose, or corroded, the thermostat will not function to its fullest capacity. After tightening wires that appeared loose or replacing any corroded wires, check to see if you can turn on your AC. 

5. Double-check the placement of your thermostat sensors.

Another potential issue to consider is the placement of your thermostat sensors. The thermostat sensors tell your thermostat what the temperature of your home is. If placed in a poor location, the temperature sensors may not communicate the correct temperature of your home to your thermostat. As such, these sensors may prevent your AC from turning on.

A good indicator that your thermostat sensors have been placed in a poor location is if the temperature on your thermostat appears much higher or lower than it feels in your home. (You can also purchase a hygrometer to place in your home, which reads the temperature and humidity of your home; they cost around $10). 

If that’s the case, try placing your thermostat sensors in a more central location of your home, away from windows and appliances. When your thermostat reaches a temperature higher than it is set for, your AC should kick on. If it still fails to turn on, this is not the issue.

6. The thermostat itself has defects. 

Last but not least, it’s possible that your thermostat itself has defects that are out of your control. As a last resort, you may want to uninstall your existing smart thermostat and try re-installing your old thermostat. If you’re able to re-install your old thermostat and turn on your AC, then the new thermostat was the issue. This is a sign that you may need to run to the store and exchange that thermostat for a replacement. 

Should You Contact an HVAC Professional?

We hope that this article answers the question, “Why is my AC not working after changing the thermostat?” Once you’ve identified the issue, you may be able to resolve it yourself. However, if you are having trouble identifying the issue, it may be time to consider contacting an HVAC professional.

At Edge Heating & Air, our team of expert HVAC technicians is familiar with all things HVAC. From fixing your thermostat to replacing your entire HVAC system, we’re here to help with our 24-hour emergency services.

To fix your AC today, call (951) 304-9658 or schedule your service online


More Posts You May Find Interesting