As summer approaches and flip-flops become standard weekend attire, practically everyone around Atlanta is running their air conditioners. And if you’re the type who likes things cool indoors – think 68 to 72 degrees – you’ll probably be running your AC a lot.

But here’s the thing about air conditioners (and it’s no big secret). They don’t always work when you need them to.

While they can usually be repaired, it’s no fun waiting for an AC to get fixed when it’s 90+ degrees outside! When possible, you want to avoid any problems that might cause your air conditioner to malfunction. That starts with knowing why your AC might not be cooling your home.

Here are the 10 most common reasons your air conditioner isn’t working:

1. Your thermostat batteries are dead.

Yup. Sometimes, there’s nothing wrong with your air conditioner at all. Your thermostat isn’t displaying anything, and it’s because the batteries are out of juice.

The solution? Switch ’em out. Simple as that.

Changing the thermostat batteries should be your first line of defense when the screen is blank, and you don’t know why. You can certainly call an HVAC company to fix this, but that costs way more than a few areas.

Bonus (or Reason #1.5): Make sure your thermostat is set to “cool.” If it isn’t, you’re either running the heat or you’re just spinning the fan!

2. The indoor disconnect switch is off.

This could have been turned off by accident, especially if it’s in your attic or garage. Someone may have bumped it… or something. It happens.

Anyway, make sure the disconnect switch is set to “on” before doing any additional troubleshooting. This simple fix might be all you need.

3. The outdoor disconnect switch is off.

Wait. Do you mean there’s another disconnect switch? Yes. Yes, there is.

Building codes mandate that switches be installed next to your AC’s indoor and outdoor units. The outdoor one might have been switched off for any number of reasons, and it’s pretty easy to check and reset if necessary.

4. You’ve got a tripped circuit breaker.

Check your breaker box. Is one of the breakers tripped? It might be the one that connects to your HVAC system. Reset it and try the AC again.


Keep in mind that breakers often trip because a circuit is overloaded. If the breaker trips again, consider shutting off other equipment that may be contributing to the problem. Or, if you don’t know why it keeps tripping, call an HVAC professional to diagnose the problem.

5. You blew a fuse.

You might have blown two fuses: the literal fuse connected to your thermostat and, if you’re angry about your AC not working, an internal “fuse.”

Anyway, a blown fuse between an AC and your thermostat is kind of like a bad battery in your car. You’ll need to have it replaced before the machinery can do its thing. Unless you’ve got special training, this isn’t a fix to attempt yourself. It’s best to call a heating and air company to fix the problem.

6. You’ve got a blown transformer.

Same deal as the blown fuse. Ok, it’s a different problem, but the outcome is identical. Your AC won’t work until you replace the bad transformer.

You might also have a bad contactor in the outdoor unit. That’s what often leads to a blown transformer, so you’ll need to have that switched out as well. Wiring issues, like a short in the wire, can also cause this problem.

7. Starting components are on the fritz.

To run properly, most air conditioners depend on at least two capacitors inside the outdoor unit. These components – one is technically the “start” capacitor and the other is the “run” capacitor – look like giant batteries. They hold power and allow your air conditioner to turn on and stay on.

Unfortunately, they have a limited shelf life. Capacitors fail eventually and need to be replaced by an HVAC pro.

8. Your indoor and/or outdoor coils are dirty.

Sometimes, your thermostat is set to “cool,” but the air coming out of your vents isn’t cool at all. When this is the case, you might just have a dirty coil.

You’ve got two AC coils, one in your outdoor unit and one in your indoor unit. They can get dirty if you don’t have your HVAC system serviced regularly.

Over time (and if they get really dirty), the system won’t be able to remove heat from your home very efficiently. You’ll just circulate air that’s more or less the same temperature, and you’ll never satisfy your thermostat setting.

9. You need to change your dirty filter.

If you aren’t changing or cleaning your air filter per the manufacturer instructions, it’s probably getting dirty. Over time, filters get so clogged with dust and gunk that they restrict airflow to your HVAC system. That’s bad.

Without enough airflow, the system can literally freeze up – ice on the coil and everything. It won’t cool properly.

Other reasons your coil might freeze up include:
  • Refrigerant leaks
  • Improper refrigerant charge
  • Closing half or more of your supply vents
  • Obstructed return or supply vents

A dirty air filter is the most common offender, but a range of issues could cause this problem.

10. Somebody damaged the HVAC components.

Fact: If you bang on something enough, it’ll break. Heating and air systems are no exception. So…

Maybe your landscaper accidentally busted the refrigerant line.

Or maybe you pulled a wire by mistake when you were working on an unrelated project.

Perhaps your kids threw a heavy ball into your outdoor unit and damaged something. Anything is possible.

The best solution to all these problems? Have your HVAC system serviced regularly!

Most of these problems are preventable. When you hire an HVAC pro to analyze your system regularly, you can usually avoid the agony of a broken air conditioner. A thorough inspection and tuneup should identify problems before they become problems.

That way, you can fix them today instead of later… when they’re more expensive.

At PV Heating, Cooling & Plumbing, our AC service agreements are the best in Atlanta. That’s not a claim we make lightly!

Not only do you get two inspections per year – one for the cooling season and one for the heating season – you also get…
  • outdoor coil cleanings
  • drain line flushing
  • condensate pump cleaning, and
  • every operational/integrity test needed to uncover potential problems.

Oh, and we also give 15% parts discounts to clients with service agreements. And $0 service charges, seven days per week, holidays included. And a lifetime supply of 1″ air filters. And priority client status. It’s a pretty sweet deal!

So go ahead and have your AC inspected before this bad stuff happens.

You’ll rest easy knowing that it works. You’ll also save big by avoiding expensive problems in the first place.

Contact us today to schedule your inspection!

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