Home AppliancesAir Conditioner

What Does “H3” Mean in Air Conditioners?

Air Conditioner

Air conditioner manufacturers use a variety of error codes, so you don’t feel confused when your AC unit suddenly stops working.

These error codes let you identify the root cause of the potential malfunction, thus also allowing you to take the right steps to resolve it.

One of the errors you might encounter when running your AC is the H3 error. Although not a preset error on every air conditioner model, this specific code should tell you if it isn’t safe to keep your AC unit running.

  • The H3 error code on an air conditioner works as compressor overload protection.
  • It shuts your AC off when the temperature gets too hot.
  • H3 error might also point to compressor damage and failure.
  • Sometimes, all you need is to power cycle or reset your AC.
  • Worst case scenario might call for the help of an HVAC professional.

The H3 error code doesn’t show on every air conditioner unit, but it may have a counterpart in older models. Understanding what the H3 error means lets you take the right steps to avoid further damage to your unit.

What Is the H3 Error Code on an AC?

H3 Error Code On An Ac

Certain AC brands and models will display an H3 error code. This shows on the LED display when the air conditioner detects high levels of humidity or, in some cases, excessive ambient heat.

Your unit might shut off as the H3 error code flashes on the AC display.

Manufacturers use the H3 error code as compressor overload protection. That’s because excessive heat and humidity can cause major damage to the compressor.

So when the unit detects temperatures over 90°F, it will blink H3 and turn off the unit to protect the compressor against overheating.

Other models use the H3 error code to indicate compressor failure due to other reasons. For example, a damaged, malfunctioning compressor will struggle to circulate refrigerant and thus fail to remove heat.

What To Do When the H3 Error Code Shows

H3 Error Code

If your AC displays the H3 error, here’s what you can do:

  • Turn off the unit.
  • Inspect the exterior for debris, dirt, and any blockage.
  • If the condensers and filters are caked with dirt, this could cause overheating. Clean them before turning the AC on again.
  • If the components are clean, wait 15 minutes before turning the unit back on.
  • If it shows the H3 error again, turn off the unit and the breaker for another 15 minutes.
  • In case these steps don’t work, reset your unit.
  • If the H3 error persists, call in a professional.


The H3 error on your air conditioner tells you if it’s too hot to run your unit. Giving your AC time to recuperate from the temperature should be enough to get it working again.

You might need to perform routine maintenance and cleaning to restore functionality. But if worse comes to worst, you may have to call in an expert to repair your AC.

Frequently Asked Questions

How Do I Reset My AC?

Every air conditioner comes with a rest button that you can locate somewhere in the area of the control panel.

Hold it for three to five seconds, then release it to reset your AC. Instructions may vary from model to model. Make sure to check your user manual for specific reset directions.

What Temperature Is Too Hot for an AC?

Most air conditioning units are designed to withstand outdoor temperatures of up to 90-100°F. The unit may work harder to cool your space when the temperature exceeds this.

In effect, the unit could sustain damage to a number of its components, particularly the compressor.

Leave a Comment

Your email address will not be published. Required fields are marked *