When the summer heat is unbearable, the last thing you need is an air conditioner that won’t turn on (or, an air conditioner blowing hot air). Today, the experts at Summers Comfort Heating & Air are helping you troubleshoot a thermostat set to cool but AC not turning on, so you can fix it – or know when to call a professional. Fortunately, there are several common reasons why this happens, and many of them have simple solutions, so let’s dive in!
Quick Troubleshooting Checklist For A Thermostat Set to Cool but AC Not Turning On
Before diving into complex problems, check these quick fixes:
- Ensure the thermostat is set correctly
- Check the circuit breaker
- Replace thermostat batteries
- Inspect the air filter
- Look at the outdoor unit and ensure there’s no debris blocking the condenser coils.
If none of these quick fixes solve the issue, you may be dealing with a more serious problem. Below, we explore the most common causes and solutions.
Common Reasons For A Thermostat Set to Cool but AC Not Turning On
Thermostat Issues
Your thermostat is the brain of your HVAC system. If it’s not working correctly, your AC won’t respond.
- Dead or weak batteries – If your thermostat is battery-powered, replacing the batteries may fix the problem.
- Incorrect settings – Double-check that it’s set to “Cool” and the fan is set to “Auto” instead of “On.”
- Calibration problems – An old or inaccurately calibrated thermostat may need to be calibrated.
Tripped Circuit Breaker
A power surge or an overloaded circuit can trip the breaker, cutting power to your AC.
- Locate your electrical panel and check if the breaker connected to your AC unit has flipped.
- If the breaker trips repeatedly, it may indicate a deeper electrical issue that requires professional repair.
Dirty or Clogged Air Filter
A dirty air filter can block airflow, causing your AC system to overheat and shut down as a safety measure.
- Replace or clean the air filter every one to three months to keep the system running smoothly.
- If replacing the filter doesn’t solve the issue, there may be another airflow-related problem.
Frozen Evaporator Coil
If the AC is running but no cold air is coming out, the evaporator coil may be frozen.
- Turn off the system and let the ice melt before restarting.
- Check for clogged filters, blocked vents, or low refrigerant levels as possible causes.
Faulty Capacitor or Contactor
Your AC’s capacitor and contactor are essential for powering the compressor and fan.
- If you hear a click but no startup, a faulty capacitor may be the issue.
- Contact a professional HVAC technician can safely replace these components.
Outdoor Condenser Unit Issues
Your outdoor unit plays a vital role in cooling your home. If it’s dirty or damaged, your AC may not function properly.
- Ensure there’s no grass, leaves, or dirt blocking airflow around the condenser.
- Listen for unusual noises, which may indicate a mechanical issue.
Refrigerant Leak
If your AC is running but not cooling, low refrigerant could be the culprit.
- Signs of a refrigerant leak include hissing noises, ice on refrigerant lines, and warm air from vents.
- Only a licensed HVAC professional can properly recharge the refrigerant and fix leaks.
When to Call an HVAC Professional For A Thermostat Set to Cool but AC Not Turning On
Some issues require professional help which mean searching for “HVAC companies near me”. Let’s take a look at the signs that may require professional help:
- Your AC won’t turn on even after troubleshooting.
- Your AC is turning on, but not blowing cold air.
- The circuit breaker keeps tripping repeatedly.
- You hear buzzing, hissing, or grinding noises from the system.
- The unit is leaking refrigerant or blowing warm air.
Final Thoughts: Your Thermostat Set to Cool but AC Not Turning On
A malfunctioning air conditioner can be a major inconvenience, especially in an environment with high heat. If your thermostat is set to cool but AC is not turning on, start with simple troubleshooting steps. However, if the problem persists, it’s best to contact a professional. Summers Comfort Heating & Air in Denham Springs, LA. offers expert services and solutions to keep your home cool and comfortable in every environment.
How can we help you?
