AC Repair Guide: How to Troubleshoot and Fix an Air Conditioner
Air conditioning stopped working, and you're beginning to feel the heat? Here are some telltale signs your AC unit needs help:
A humming noise from your air conditioner
You've seen a spike in energy bills
Your air conditioner takes some time to start a cooling cycle once you turn it on
The air conditioning system shuts off at random
No cold air blows into your home while the air conditioner runs
The air conditioning system doesn't turn on at all
Smoke or a burning smell from exterior air conditioning components
Don't start sweating just yet; you can try fixing some of these AC issues on your own. If you're experiencing the most common problems, such as noise or low cooling, we've compiled several handy tips you can use to tackle these issues yourself.
Vibrations and noise in your AC unit
Loose nuts and bolts generally cause vibrations. Listen for where these vibrations are coming from, and keep an eye out for any loose bolts outside your air conditioning unit. Giving these a quick tightening should solve most noise issues. If the noise persists, do the same to any bolts you spot when inspecting the rest of the unit.
Your air conditioning unit won't turn on?
If you are experiencing more serious issues related to your unit, such as no air at all, then let's troubleshoot. Read below for a few tips and tricks professionals usually use to figure out the root cause of your AC troubles.
Check your thermostat
Sometimes you can solve AC issues in a jiffy by replacing the batteries in your thermostat! It may seem silly, but we've seen it all. Check the batteries first. If you're good on that front, keep the thermostat inspection going - revise all of the settings, and make sure you're following the instructions in your owner's manual to triple-check that the thermostat is not the culprit.
Check the fuses
If your AC unit is not turning on at all, it could be the result of a blown fuse. You can check if the fuse is no good with a multimeter tool or VOM, typically used by HVAC professionals. Most multimeters measure current, voltage, and resistance. If you have a voltmeter or multimeter, you can test the fuses by yourself. BE sure you know what you are doing as you work with live electricity. Readings between 220-240 are healthy, whereas a line or no reading signifies a blown fuse.
Your AC still won't turn on or start running?
Check your air filter
We've talked about this before, but remember to check your air filters. If they're dirty, they need replacement. Otherwise, you risk putting extra pressure on your system and breathing polluted air that can cause health issues. Ideally, it would be best if you replaced them every 90 days. They're inexpensive, very easy to replace, and can save you a lot of money in the long run. Maintenance is always the best way to avoid surprises later down the road.
Clear the area around your AC unit
Ensure there are at least two feet of space around your AC unit. If it doesn't have enough room to breathe, it won't work correctly and can contribute to costly breakdowns.
Leaking Ducts
Repair those ducts. If they're broken, then you're losing money. Cool air is lost through cracks in the ductwork in spaces such as your attic or basement, particularly if your home was built over 10 years ago. Patch these up with duct tape to save money and feel more comfortable at home.
Turn off the power
Turn off the AC fuse breakers in your fuse box or pull the disconnect block out of the box next to the AC unit to avoid a nasty shock. Then use a voltage tester to check that they are truly off before proceeding.
AC contactor relay and start/run capacitors are often the culprits, so consider replacing these first, mainly if your unit is over five years old. They are relatively cheap.
To buy replacement parts, find the serial number for your unit. It's probably on a plate on the exterior AC unit, and you can then search for details of the pieces you need using this number.
Clean the Condenser coils
A central air conditioner's condenser coil collects the heat from your home's warm air and releases it outside. These coils are different tubes filled with refrigerant liquid. Your condenser coils sit directly behind the condenser "fins"—the thin metal wiring that covers your outdoor AC unit.
Sometimes these coils can be obstructed, therefore, requiring cleaning. This is the number one cause of AC's not working as expected. The great thing is that it's also another quick fix.
Just turn off your electricity, then remove the outer box of your unit. Remove debris like leaves and sticks from the condenser unit. Then you can use a garden hose to hose down the coils gently.
Check the access panel
Follow the cables from the house to find the access panel. Remove the outer panel and make sure there aren't any rodent nests or evidence of chewing on wires.
If you see any broken wires or chewed insulation, this is where a professional will have to come in. Or, if you feel confident working with electricity and repairing on your own, first, discharge the capacitor, carry out the repairs and clean out any debris.
Replace the Start/Run Capacitors:
What does a capacitor do? The capacitor stores and releases electricity when you turn your unit on or when your fan needs an extra jolt of power. It also smooths out energy spikes to help protect the fan motors from damage. Some telltale signs you have a bad capacitor:
Smoke or a burning smell from exterior air conditioning components
Your air conditioner takes some time to start a cooling cycle once you turn it on
The air conditioning system shuts off at random or doesn't turn on at all
Unfortunately, capacitors degrade slowly over time or can even fail suddenly. When this happens, it puts more stress on the fan motors. It's essential to replace them once every five years when performing maintenance to help avoid a much more costly fan motor failure.
Look for signs like cracks, bulging, and oozing liquid from the capacitor and circuit board. HVAC professionals will also use the multimeter tool we mentioned before to test if there is enough charge.
Wrapping up
If these repairs haven't worked or you are not comfortable tackling them on your own, consider getting the pros in. We offer free in-home consultations, where we send one of our experts to come in and play with electricity instead. ;)