HVAC Hums and Blows Hot Air

My HVAC Just Hums and Buzzes But Doesn’t Turn On

The Problem: Your A/C thermostat clicks on but only warm air is coming out of your vents.

You check your outside unit and notice that the outdoor unit is humming like normal but the fan isn’t spinning and is making a buzzing noise.

So, what exactly is the problem?

If your outdoor A/C unit is humming but the fan isn’t running, that most likely means you have a bad fan capacitor which is a common problem in the Tallahassee, FL area and everywhere else in the USA.

Thankfully, there’s a short-term fix that’ll keep you cool until Tallahassee Air Conditioning & Electrical can get out to your home or business to get your capacitor replaced.
We’ll show you that cheap trick later in this article. However a little education can go a long way so first let’s take a look at why capacitors are so important in the first place.

What is a capacitor?

A capacitor is a small, cylinder-shaped metallic object that sits on the side of your outdoor unit. It acts like a battery and stores large amounts of energy. Tallahassee Air Conditioning & Electrical stocks both standard capacitors and turbo capacitors for heavy demand systems.

Photo source: doityourself.com

In the case of air conditioners, capacitors are used to kick-start the compressor, the outdoor fan motor, and the blower fan (indoor unit fan).

You see, large appliance motors require up to 5 or 6 times more energy at startup than they require when running continuously. Capacitors offer that extra jolt of electricity needed to get motors started and/or to run continuously.

Why did my capacitor “go bad”?

Just like a battery, your capacitor will weaken and lose the ability to hold electrical charge over time. They’ll also have a shorter lifespan if they suffer some sort of damage, like from high temperatures or high voltage such as lightning strikes.



Some of the visual signs of a bad capacitor include:

  • A swollen, “mushroomed” top
  • A capacitor that is corroded or rusted out on bottom
  • Fluid leaking from any part of the capacitor

Source: fixya.com

So, if the capacitor connected to your fan motor goes bad, the fan will fail to start. And this prevents your unit from moving the heat from inside your home to the outdoors (which explains why the air coming from your vents is warm instead of cool).

Eskimo Joe’s short-term solution for a bad capacitor

Need a quick fix for your failed fan motor capacitor?

Turn on the A/C unit and take a long, thin object (a stick or screwdriver will work fine) and use it to push the fan blades inside the compressor. (The Compressor is Outside)

This should provide the “kick” the fan motor needs to get up to speed.

Please be sure to take safety precautions when doing this so that nobody gets hurt.

Photo source: youtube.com

Note: if this doesn’t get your fan running, you most likely have a bad fan motor and will need to have Tallahassee Air Conditioning & Electrical, LLC

The long-term solution for a bad capacitor

If the capacitor connected to your fan motor is weak or has finally died and won’t start your fan, you need to have a professional replace it as soon as possible.


When a capacitor fails, the motor it is connected to will still try to come on. And most of the time, the motor won’t be able to start on its own. This stalling can cause the motor to burn out and need expensive replacement soon.

The sooner you are able to replace the capacitor, the more money you will save yourself in the long run.

Note: Although it is possible to replace a capacitor on your own, we don’t recommend it unless you have experience working with the electrical components of your air conditioner. 

Looking for an A/C tech to replace your capacitor?

Ready to get your air conditioner running properly?

Live in the Tallahassee, FL area?

Just call Eskimo Joe at Tallahassee Air Conditioning & Electrical, LLC and schedule your appointment today. We’ll send a professional out to diagnose and repair your A/C unit in no time.

Sep 21, 2016 Uncategorized

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