Leonard Splaine Top reasons why your AC isn’t working

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Summer’s hot weather is back in full force. The last thing you want when the temperatures outside are rising is to be wondering why your air conditioner isn’t working.

Unfortunately, like everything else, air conditioners can break down and when this happens on a hot day it can be very miserable

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. Then start with knowing why your AC might not be cooling your home.

In this article, we’ll review 10 of the top reasons why your air conditioner isn’t working and is unable to cool your home. If you’re experiencing AC problems, call Leonard Splaine this summer for AC repair.

1.  The Batteries in Your Thermostat are Dead

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.

This is an easy fix! simply change out the batteries.

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 AAAs.

Tip: 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.  Your Indoor Disconnect Switch is Off

Particularly if your switch is located in an attic or the garage, it may have been accidentally bumped and switched off. 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.

There is also a switch installed next to your outdoor air conditioner unit. You may not know this, but 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. Do you have a Tripped Air Conditioner Circuit Breaker?

Make sure you check your breaker box. Is a breaker tripped? It could be the one that connects to your HVAC system. Reset the breaker and try your air conditioner 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.

Actually, 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 contractor 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

If your thermostat is set on cool but the air coming out of your vents is not, a dirty coil may be the problem. Your air conditioner actually has two coils. One in your outdoor unit and one in your indoor unit. If you don’t have regular routine maintenance performed on your HVAC, these coils can become dirty. If they are allowed to accumulate a lot of dirt, the system will not be able to remove heat from your home efficiently. What happens, in this case, is that air more or less the same temperature, is just recirculated, never reaching the temperature your thermostat is set on.

9.  Your Dirty Air Filter Needs Changing

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.

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.


All of the problems listed above are preventable. The best way to avoid these common problems and many others is to have your Heating and Air system serviced twice a year. Once before the heat cycle and again before the cooling cycle. An inspection and tuneup will identify small problems before they become large and expensive repairs or result in a system replacement.

If your air conditioner is not keeping you cool, give Horne Heating and Air conditioning a call today at (571) 410- 3555 or contact us to schedule an appointment for service with one of our trained technicians.

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