Thermostat Clicks But AC Does Not Turn On
Nothing’s worse than a hot day with a malfunctioning air conditioner. If your thermostat is clicking but your AC remains stubbornly silent, it is probably a power supply problem, mechanical failure, or improper thermostat setting.
In this article, we’ll talk about potential causes behind this issue and provide practical troubleshooting steps to help you get your AC back up and running. Whether it’s a simple electrical problem or a more complex mechanical issue, we’ll cover it all. So, let’s get started and find a solution to your AC woes.
Why Is My Thermostat Clicking But the AC Is Not Turning On?
When your thermostat clicks but the air conditioner remains unresponsive, it often points to one of the following causes.
1. Power Issues with the AC Unit
Even though the thermostat is clicking, the AC unit itself may not be receiving power. This could be due to tripped circuit breakers, blown fuses, or problems with the wiring.
2. Thermostat Wiring or Settings
Sometimes the problem isn’t with the AC itself but with the thermostat’s wiring or settings. Loose, damaged, or corroded wiring can prevent proper communication between the thermostat and the AC.
3. Airflow Restrictions
Poor airflow can prevent the AC from turning on, even if the thermostat is working fine. Clogged filters or blocked vents can restrict airflow, causing the AC system to shut down to prevent overheating.
4. Frozen AC Coils
Frozen coils can stop the AC from functioning, even if the thermostat is clicking. This usually happens when airflow is restricted or there is a refrigerant issue.
5. Capacitor or Contactor Failure
The capacitor and contactor are vital components that help the AC unit start and run smoothly. A failed capacitor won’t be able to send the initial surge of energy the system needs, while a faulty contactor can disrupt the power supply to the unit.
How to Fix AC That Won’t Turn On Despite a Clicking Thermostat?
Now that you know the potential causes of your malfunctioning AC, here’s some help on whether to resolve the problem yourself or call for expert assistance.
1. Solving Power Issues
Go to your electrical panel and check if the breaker for your AC unit has tripped. If it has, reset it by flipping the switch off and then back on.
However, if the breaker trips again after resetting, this indicates a more serious electrical issue, and you should call a licensed HVAC technician to assess the problem.
Additionally, check for any blown fuses in the disconnect box located near the AC unit. Replacing a blown fuse may resolve the issue.
2. Tweaking Thermostat Wiring or Settings
Check your thermostat’s settings to make sure it’s set to “cool” mode and that the temperature is lower than the current room temperature. Ensure the fan is set to “auto” or “on.” Also, replacing the batteries on your battery-powered thermostat might help if it has been sending inconsistent signals due to low power.
If you’re comfortable working with electrical components, gently remove the thermostat from the wall to inspect the wiring. Tighten any loose wires or replace any visibly damaged ones. However, if you’re unsure about handling this, it’s safer to have a professional handle it.
3. Removing Airflow Restrictions
Check and replace your air filter if it’s dirty or clogged. Air filters should typically be replaced every three months, but you may need to replace them more often if you have pets or live in a dusty area.
Walk through your home to make sure all air vents are open and unobstructed by furniture or other objects. Blocked vents can disrupt airflow and lead to AC performance issues.
4. Frozen AC Coils
Turn off the air conditioner at the thermostat and allow it to thaw for a few hours. Turning the fan to “on” can help speed up the thawing process.
After the coils have thawed, turn the AC back on and monitor its performance. If the coils freeze again, there could be a more serious issue, like a refrigerant leak or ongoing airflow problems, which will require a technician’s expertise.
5. Capacitor or Contactor Failure
Diagnosing and replacing a bad capacitor or contactor requires professional help, as these are internal components that are difficult to access and test without the right tools. If you suspect this is the issue (e.g., if your AC hums but doesn’t start), contact a certified technician to replace the faulty part.
Frequently Asked Questions
How do I manually test my thermostat?
Ask a friend or family member to help you. Have one person stand near the thermostat and another stand near the furnace. Slowly turn the thermostat from ‘off’ to ‘heat‘ and gradually increase the temperature. Both the thermostat and furnace should make noise.
How do I reset my AC thermostat?
Turn off your air conditioner. Find the reset button on the thermostat’s control panel. Use a soft brush to carefully clean any dust or dirt from the thermostat’s parts. Press and hold the reset button for 5-10 seconds until the screen goes dark.
Conclusion
By addressing the common causes we listed here, you can often resolve an AC unit that doesn’t turn on, even when the thermostat clicks. If troubleshooting doesn’t solve the problem, it’s always wise to consult a professional to prevent further damage and keep yourself safe as well.
