It doesn’t take long for things to heat up when your air conditioner won’t turn on—especially in the northwest. Here are the most common reasons your air conditioner might not be working and some tips to get it running again.
One of the most common culprits is the thermostat. Make sure it’s set to “cool,” turned on, and adjusted a few degrees below the current room temperature. If it uses batteries, try replacing them. If that doesn’t help, the internal sensor may be malfunctioning. If your thermostat isn’t reading temperatures correctly, it could prevent your AC from starting. In that case, it may be time for a replacement.
A clogged air filter restricts airflow, which can cause your AC to freeze up and shut down. Filters should be changed every 30–60 days, more often if you have pets or allergies. If yours looks dirty—or you can’t remember the last time you changed it—swap it out. If your system was frozen, wait for it to thaw before restarting it.
Head to your home’s electrical panel and look for a tripped breaker. If the AC breaker is in the “OFF” position, flip it back to “ON.” If the breaker keeps tripping, stop trying to reset it. There are most likely bigger electrical issues at play.
This switch often looks like a regular light switch and is usually located near your furnace or air handler—in a closet, attic, or crawl space. If someone accidentally flipped it off, your AC won’t run. Just flip it back to “ON,” and label to avoid future confusion.
Make sure external shutoff switch is in the “ON” position so your system can power up.
Some AC units have a reset button—if yours does, press it and wait a moment before restarting your system. If you can’t find one, try resetting manually by turning the thermostat off for 5–10 minutes, then turning it back on.
If you spot ice on your air conditioner, give it time to thaw before restarting it. Ice buildup can result from poor airflow, refrigerant issues, or dirty coils.
A blocked condensate drain can prevent your AC from turning on as a built-in safety feature. You can try using a wet/dry vacuum to clear the line. Pour a bit of water down the drain to test it—if it flows freely, you’re good to go.
Check thermostat settings.
Change the air filter.
The pilot light is on (if applicable).
Tripped breaker in your home circuit
Make sure all vents are open and unblocked.
If your Air Condition still does not turn on, Call Fast Heating and Air.
We are authorized dealers and installers of the most common and trusted furnace manufacturers.
If you’ve tried these steps and your AC still won’t turn on, don’t sweat it—Fast Heating and Air has you covered. Our trained technicians will quickly diagnose the problem and recommend the right fix, whether it’s a simple repair or a new installation.
If your air conditioner does not turn on, it could be due to several issues including a tripped circuit breaker, thermostat not working, dirty air filter, or a clogged condensate drain. Start by checking your thermostat settings and circuit panel.
When your AC is not turning on, check for a tripped breaker, ensure your thermostat is set to “cool,” inspect the air filter, and confirm the outdoor AC disconnect switch is in the “ON” position. If these don’t help, contact an AC repair service.
If you’re wondering how to reset your air conditioner, look for a reset button on the unit. If it doesn’t have one, turn off the thermostat for 5–10 minutes, then turn it back on. This can often restore power to the unit.
Yes. A dirty air filter in your AC can restrict airflow, causing the system to overheat or freeze, which may shut it down. Replace your filter every 30–60 days, especially if you have pets or allergies.
A frozen air conditioner is often caused by restricted airflow or low refrigerant levels. Turn off the system and allow it to thaw before restarting. Also, check your filter and airflow from vents.
A clogged condensate drain can cause your air conditioner to shut off as a safety measure. Use a wet/dry vacuum to clear the drain or pour water to test for blockages. If it doesn’t drain, call an HVAC technician.
Blocked AC vents prevent proper airflow and can cause your system to shut down or freeze. Make sure all supply and return vents are fully open and not covered by furniture or rugs.
Absolutely. A thermostat not working correctly—like one with dead batteries or faulty sensors—can prevent your air conditioner from turning on. Replace the batteries or consider upgrading to a smart thermostat.
To troubleshoot an AC not working, start with these steps:
Check thermostat settings
Inspect the air filter
Reset the system
Check breakers and switches
Clear any visible ice or drain blockages
If those don’t work, it’s time to call an AC repair service.
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