Panasonic air conditioner error code H99

If your Panasonic air conditioner is displaying an “H99” error code, this indicates that the indoor unit is in freeze protection mode, which can be solved through troubleshooting.

Frozen air conditioners are a common problem, and this can end up causing some damage in your home if the issue is not fixed.

The “H99” error code that displays on Panasonic air conditioners is meant to warn you that the unit has activated freeze protection mode and there are several troubleshooting options that can resolve the issue and clear the error code.

Why air conditioners sometimes freeze up

It may seem like a good thing that your air conditioner is so cold that it begins to freeze, but actually, this does not indicate that the unit is functioning optimally and it is usually because of an issue with one of its components.

Freezing is a common air conditioner issue, but if a frozen air conditioner keeps operating despite the freezing, eventually, a big block of ice will build up and your unit may even start spitting ice out of its vents.

This can cause damage to your floors and furniture, not to mention, to the components of your air conditioner, because continued operation with ice buildup can damage components, including the compressor and the fan.

Another consequence of a frozen air conditioner is the increased energy consumption.

Panasonic air conditioner error code H99

Because of how much damage a freezing air conditioner can cause, air conditioner manufacturers try to design their units to prevent freezing from happening in the first place.

Panasonic’s solution is for your air conditioner to warn you when your air conditioner might begin to freeze.

This means that if your Panasonic air conditioner displays an “H99” error code, your air conditioner has activated the “Indoor operating unit freeze protection” protocol, which tells you that your unit will start freezing if it continues to operate.

This error code can be caused by many things, ranging from a lack of airflow to an interrupted circuit or a dirty or faulty thermostat.

All of these issues can cause your air conditioner to freeze if they are not fixed, and your best course of action in this case is to work through a troubleshooting list of possible issues so that you can find and fix the issue, like:

  • Check that your air conditioner has sufficient airflow
  • Check that the circuit is not short
  • Check that your air conditioner thermostat is working properly

Once you have worked through these troubleshooting options and fixed any issues or parts along the way, the H99 code should be cleared, and your air conditioner can continue working as it did before the error code.

How to check that your air conditioner has sufficient airflow

In order for your Panasonic air conditioner to have sufficient airflow, the unit needs to be able to take in and expel air into the room.

If the H99 error is caused by a blockage in the airflow, you can fix this by removing any furniture, blinds, curtains, or plants that may be blocking the vents of your air conditioner.

You can also improve the airflow in your air conditioner by cleaning the air filters. Over time, dirt and debris may build up on these filers, which can make it difficult for air to pass through the filter.

When there is no hot air passing over the evaporator coils, they will get too cold and start freezing. You can prevent this by cleaning the air filters in your unit with a vacuum or a soft brush and lukewarm water.

How to check that the circuit is not short

Your Panasonic air conditioner could also be displaying the H99 error code if there is a short somewhere in the system that is causing the unit to freeze up.

If the compressor and fans are not working correctly, your air conditioner will not be able to move the refrigerant and cold air properly and the unit can get too cold and freeze.

In this case, you need to call a professional to come and check that all of the electrical components in the unit are working as they should, or if you are savvy, you can check for the short yourself using an electric multi-meter.

Panasonic air conditioner error code H99
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How to check that the thermostat is working properly

In order to ensure that the internal thermostat or temperature sensor of your Panasonic air conditioner is working correctly and not giving the unit incorrect feedback, which is causing it to get too cold, you need to find the thermostat, which will look like a black tube.

You can then compare the placement and appearance of your thermostat to the illustration in the owner’s manual to figure out if the placement is correct and if the thermostat is working properly.

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