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Common Problems To Look For When Your AC Unit Stops Working

Technician Installing HVAC Unit

It’s bound to happen eventually during a hot summer day. Every homeowner should know how to troubleshoot their AC unit because problems are more likely to arise during times of heavy use, like the scorching summer months.

If you have central air, you understand (and maybe even take for granted) the cool relief of entering your home to escape a hot and humid day. Everyone is looking for ways to keep their homes cool during the summertime. However, nearly every homeowner has also experienced the sweaty and sticky misery that ensues when this appliance stops working.

You might be tempted to immediately call a licensed HVAC technician for a quick fix, but there are DIY air conditioner troubleshooting tips that might save you some money. If you want to know what to check when the AC stops working, then read these problem-solving solutions.

Air Conditioner Troubleshooting

Thermostat Settings

The most obvious place to look when your home feels warmer is your thermostat. If your air conditioner is switched to the wrong setting, it could result in warm or hot air coming from the vents. Likewise, your HVAC system could be turned off completely, leaving your home’s air feeling stagnant and stale.

As soon as you sense that something might be wrong with your air conditioner, go to your thermostat and verify that it is set to “cool” and not “heat” or “off.” Although it might sound silly, this mistake happens more often than you’d think — especially during seasonal transitions.

Furnace Fan

The next thing you'll want to check after your thermostat settings is your furnace fan. The furnace fan blows cold air into the duct system. Once you ensure your thermostat is set to the cooling mode and lower the temperature setting, check to see if the furnace fan starts up. If it doesn't — even after resetting the breaker on the main electrical panel — then you've likely identified your problem. If it does, then you'll have to look elsewhere for a solution.

HVAC Filters

If your furnace fan is operating normally, then the air conditioner might be functioning properly, but there is a blockage preventing circulation. Check your HVAC filters to ensure they are clean and not preventing air from freely flowing through. Ideally, you’ll want to change your filters every one to two months — especially during seasons of heavy use.

Test to see if your filters need to be changed by pulling them out and seeing if they are clogged with debris. Homeowners with horizontal HVAC units, with the return duct attached to the side of the air handler, should be able to find their filters in a slot on the intake side of the unit.

Condenser Capacitor And Contractor

Both the capacitor and contractor are located inside the condenser unit, which sits outside. The capacitor starts the condenser and the fan, so if the capacitor failed, then that is definitely the source of your air conditioner problems. 

First, listen for a clicking noise coming from your condenser unit followed by a hum or buzz. If you hear those strange sounds, then it probably means that the fan motor is attempting to start without the support of the capacitor.

Meanwhile, if the compressor clicks when your crank down the thermostat but doesn’t make a humming or buzzing noise, then the contractor (rather than the capacitor) needs to be replaced. 

Fan Motor

The last step will be to check your air conditioner troubleshooting is to check your fan motor. The purpose of the condenser fan motor is to keep the compressor from overheating. It cools down the refrigerant that moves through the condenser coils. If your AC unit’s fan motor is out of commission, it won’t be long before more parts also bite the dust without it performing its essential duties. 

If the motor that runs the condenser fan is burned out, then there isn't much that can be done except to replace it. You can attempt this yourself as long as you take the proper precautions, but it's best if you call in a professional HVAC technician.

Tried All The Troubleshooting Steps? Next Step Is To Contact The Best

Not everyone is an HVAC expert, so don’t feel discouraged if you walked through what to check when your AC stops working and couldn’t find a solution.

The knowledgeable team at John C. Flood services and repairs all HVAC systems in the Washington, D.C., Maryland, and Virginia region. We have the experience to answer all your questions  — and more importantly, the know-how to get your AC system back up and running. 

We also offer annual maintenance plans that include an annual cooling inspection. This annual check-up ensures that your system is operating at peak efficiency and that small issues are caught before they turn into big (and expensive) problems! 

If you’re confused about how to troubleshoot an AC unit, call (703) 752-1266 or contact our HVAC team online today!