Goettl Air Conditioning & Plumbing! Serving the American Southwest since 1939.

Why is My Air Conditioner Not Working?

Is your air conditioner not working or not cooling properly? In most cases, the reason an AC unit is not cooling is due to simple problems such as dead batteries in the thermostat connected to your HVAC system, a tripped breaker, or a disconnect switch accidentally turned off. Once these items have been checked, it’s time to look at the AC unit itself to determine where the problem is. 

What to Check First 

Before calling in an HVAC expert to evaluate your system, there are several things that homeowners and building managers can check when the air conditioner is not working. 

Check Air Filter 

The HVAC air filter is responsible for cleaning the air in the AC system. The filter is typically located in a slot between the return air duct and the blower. When the air filter gets dirty, this can cause poor air flow within the system, disrupting the flow of warm air to the coils, thus causing them to freeze. The result? Your air conditioner will blow warm air, or no air at all. 

Make sure to check your air filter every three months. Replace the air filter if necessary. Air filters are sold at home improvement stores.  To replace the filter, turn off the air conditioner. Remove the filter from the slot and take it to a home improvement store to find an identical replacement filter. Put the new filter in place and turn the ac back on.   

Check Your Thermostat 

Make sure to look at the thermostat box, as this is the central control station of your HVAC system. Make sure the digital controls show that the AC is set to “ON” and “COOL”. Also, check that it is set on “AUTO” instead of letting the fan run continuously. It is also important that the temperature is set low enough to activate the air conditioner. And make sure the batteries are not dead or dying.  

Check Any Disconnect Switches 

Make sure all switches are turned on and all lines are connected. The first switch should be indoors, near your furnace if you use a ducted system, or near the indoor air circulator if your system is separate from any heating components. The second will be found outdoors near the condenser unit inside a smaller box. Be cautious when checking the outdoor disconnect switch as the box may contain high voltage. Call for professional help if you’re not sure whether the switches or breakers are working correctly. 

Reset Circuit Breakers 

Once you’ve verified that all the switches are set to “on,” it’s time to head to your circuit breaker panel. If the breaker is tripped, try resetting it to see if that solves the problem. It’s important to consider that breakers trip for a reason so if it happens again, there’s likely to be an overloaded circuit or other electrical problem that needs professional help. 

Check Airflow 

Airflow can also be restricted by overgrown greenery or other obstructions to the outdoor unit. Make sure to keep any plants or shrubs near the outside AC system cut back to allow for an easy flow of air.  

If you see ice on the outdoor unit, your air conditioner may not be working properly or at all because it is frozen. To remedy this problem, turn the entire system off and change the filter out for a clean one. Then, allow several hours for all the ice to melt completely and try restarting the system to see if it works. If it’s still not cooling, turn it off again and contact an HVAC professional who can check for problems with the refrigerant. 

Check for a Coolant Leak 

Coolant is the chemical inside your air conditioner coils. As it flows through the coils, coolant is pressurized and depressurized to transfer warm air from one place to another. When coolant leaks, the air conditioner loses its effectiveness, especially when it’s hot outside. The warmer it is, the harder it is for your air conditioner to keep up.   

A coolant leak should not be repaired by you, unless you happen to be an HVAC professional. Contact a licensed HVAC expert to have your unit inspected.  

Check Condenser 

The air conditioner condenser is the part of your air conditioner that’s located outside your house, either in the yard or on your roof. Condensers expel hot air from your home to your yard. When the condenser gets dirty, the air conditioner’s job gets harder. Throughout the spring and summer, your condenser may become clogged with everything from leaves to dirt and grime. Depending on the state of your air conditioner, your ac unit may have to work very hard to keep your home cool.  

What you can do: 

  • Clean your air conditioner condenser. Cut the power to the air conditioner and remove the lid. Use a shop vacuum to suck leaves and weeds from the unit. Spray the inside of the ac unit with a hose, then replace the lid and restore power.  
  • If you’re not comfortable cleaning your own air conditioner condenser, hire a professional to do the work for you. Your HVAC professional will give your air conditioner a tune up and clean your condenser for you.  
  • Keep debris away from the condenser to prevent the unit from getting dirty. Pull nearby weeds and discard them in a trash bin. Avoid planting any shrubs or plants nearby, especially if those shrubs or plants shed leaves or needles that will eventually blow into your condenser.  
  • Promote air flow around the unit. Do not place a fence or barrier within two feet of the air conditioner unit to keep air flowing smoothly.  

When to Call for Help 

Your thermostat checks out, all the switches and fuses appear to be working correctly, a clean filter has been installed, and you’re still not getting cold air from the air conditioner. At this point, there are several components that could be the source of the problem, and all of them require a knowledgeable service technician to diagnose and repair. Also, if you hear unusual noises when the system is cycling on and off, there could be a problem with the indoor air circulator. Keep in mind that most systems will make some noises, so you’ll be listening for anything that’s abnormally loud or otherwise strange compared to the usual pops and dings. A burning smell coming from anywhere in the system means it’s time to shut it down and call for assistance.  

At Goettl Air Conditioning and Plumbing, we have the knowledge and experience to diagnose and repair all air conditioner makes and models. Our technicians always stay on top of the latest technology in the industry so you can be sure the job will be done right the first time. Contact us to schedule an appointment today.

All our technicians are "Sadie Certified"

Applicants meet the family dog before being hired and pass the Sadie test. If Sadie doesn’t like an applicant, we bet you won’t be comfortable with them in your home. We want to make it for sure that we are putting the right person in your house.