Toshiba Air Conditioner Heat Mode Not Working – What to Do?

A Toshiba air conditioner with a heat mode brings a lot of comfort. But what if the heat mode isn't working? What does this indicate, and what can you do to fix the problem? Don't worry! We've researched the answers to these questions and share them with you in this post.

The reason your AC is not heating up is probably due to a faulty reversing valve, which is responsible for changing the direction of the refrigerant. You need a professional to fix the reversing valve. However, there could be other reasons as well. See below for some ways to troubleshoot your AC's heat mode in no particular order:

  1. Inspect if ice is forming inside the unit.
  2. Check the circuit breaker.
  3. Reset the remote.
  4. Fix the thermostat.
  5. Clean the AC.

Throughout this article, we'll share with you why the Toshiba air conditioner heat mode might not function as it should. We'll discuss possible solutions to the problem. You'll learn more about AC's heat mode, so keep reading!

Air Conditioner, Wind, Heat - Temperature, Temperature, Remote Control - Toshiba Air Conditioner Heat Mode Not Working - What to Do

What to Do When Heat Mode Isn't Working in Your Toshiba Air Conditioner

Hand point Air Condition remote in Hot High temperature room.

Heat mode in an air conditioner activates the reversing valve, which helps push away cold temperature and absorb the hot air.

To explain the reversing valve briefly, it is a component inside the AC unit that redirects the flow of refrigerant between the evaporator and condenser. This results in hot air that circulates through the AC's system.

If the AC unit does not switch to heat mode, the reason could be a fault in the reversing valve. Repairing or replacing it would require knowledge and an accurate assessment. But before we end up calling a technician, we could look for other reasons and their possible solutions.

Without a specific order, you can do any of the following to activate the AC's heat mode. See the options below.

1. Inspect If Ice Is Forming

Peek inside the AC and look for ice particles that are blocking the airflow. You should remove them to let the air pass through.

Simply follow these steps to unfreeze your AC unit.

  1. Turn off the thermostat to prevent it from interfering with the temperature change.
  2. Put your AC into FAN mode so that it will continuously blow air until the ice melts.
  3. Check the quality of the filter. Clean or replace it when necessary.
  4. When the ice has melted, wait for a few minutes to completely dry the AC unit.
  5. Turn on the AC, then try switching on the heat mode.

2. Check the Circuit breaker

Electricity and electrical maintenance service, Engineer hand holding AC multimeter checking electric current voltage at circuit breaker terminal and cable wiring main power distribution board.

Air conditioners in general consume a lot of electrical energy compared to other appliances like televisions or ceiling fans. The purpose of a circuit breaker is to protect your AC from a circuit shortage or overload. This means that the circuit breaker might not be able to handle the required energy to start the heat mode.

You can check if the AC unit is compatible with the circuit breaker, especially during heat mode. Otherwise, an AC not matching the size of a circuit breaker may result in an electrical fire. You may ask an electrician to evaluate the wiring further.

3. Reset the Remote

If you're using a remote for your AC, you should check its batteries and buttons. The batteries should not look damaged, while the buttons should be tight in place. Reset the remote based on its user's manual. See also if there are obstacles blocking the AC's remote receptor.

Most Toshiba AC remotes use two AAA batteries.

See this set of AAA batteries on Amazon.

Setting up the remote will depend on the AC's model. However, you can refer to these general steps on how to reset a Toshiba AC's remote:

  1. Remove the slide cover, and insert two AAA batteries.
  2. Press the RESET button using a pencil's tip.
  3. Press the MODE button and choose the heat mode. You should see a sun symbol displayed on the remote's screen.
  4. Set the temperature. You can adjust the heat mode to a maximum of 86 degrees Fahrenheit, which is often displayed as 30 degrees Celsius.
  5. Push the FAN button to set the fan speed.
  6. Adjust the louver vertically with the FIX button, then press 'swing' to stop. You may also adjust it horizontally by hand.

close up rear view of asian young woman using smart home app to control air conditioner on mobile phone

Toshiba also has advanced technology that allows you to control the functions of your AC unit with a mobile app. We're going to share with you how to set up your mobile phone as a remote. But remember that some mobile phones may not be supported by this feature. You can ask a technician about this matter.

Refer to these steps below:

  1. Go to the application store on your mobile phone and find the Toshiba virtual remote for AC.
  2. Read the description of the app and check its compatibility with your phone.
  3. Download the app.
  4. Plug in your air conditioner and use the app to connect it to your phone.
  5. Test the app and run it by controlling the functions of the AC.

Watch this short clip on how to set up Toshiba's virtual remote for AC:

4. Fix the Thermostat

The thermostat is a device that communicates with your AC when the temperature is changing. It can shut off the AC when the desired temperature has been reached. That's why you should make sure your thermostat is programmed to respond to the AC's heating mode.

Also, the thermostat may misinterpret what temperature to display when there's another heating device running. For instance, you have a residential furnace and you want to increase the room temperature by activating the AC's heat mode. It's possible that the thermostat will read the furnace's temperature and ignore the AC's heating temperature.

This can happen when the thermostat's sensor is malfunctioning. You can fix this problem by relocating your thermostat away from heat-sensitive areas like direct sunlight. Instead, place it at the center of your home or on the living room's interior wall. If the thermostat still malfunctions, you should seek help from a technician.

Intelligent home automation system: Fahrenheit temperature multimedia thermostat

5. Clean the Air Conditioner

The airflow may be blocked by the dust particles, causing your AC to not work in heat mode. So, we'll provide you with steps on how to clean the AC quickly using only a vacuum cleaner.

You can use a handheld vacuum cleaner for your convenience.

See this handheld vacuum cleaner on Amazon.

Simply follow the steps below:

  1. Run the AC in fan mode for a few minutes to help push the dirt closer to the filter as well as evaporate moisture.
  2. Turn off and unplug the AC unit.
  3. Turn on the vacuum cleaner and switch to a moderate level.
  4. Open the AC cover.
  5. Vacuum the filter all the way through. Avoid heating up the vacuum cleaner.
  6. Close the cover when you're done.
  7. Plug in the AC and turn it on. Try also switching to heat mode.
  8. Repeat cleaning more often.

When to Turn On the AC's Heat Mode?

Logically, you should put your AC into heat mode right before the temperature reaches or drops below 55 degrees Fahrenheit. This temperature is too cold for a house. It can cause some health risks, especially to those with a weak respiratory system.

A warm room temperature, on the other hand, can help reduce moisture and mold. However, you should not exceed 90 degrees Fahrenheit. It's crucial to keep the room temperature balanced and safe at around 68-74 degrees Fahrenheit.

Air Conditioner, Wind, Heat - Temperature, Temperature, Remote Control

What Refrigerant Does a Toshiba Air Conditioner Use?

Refrigerant is a useful substance that helps both in cooling and heating mode. Toshiba uses R-410a and R-32 for their air conditioners. However, Toshiba plans to use R-32 in their split AC units.

R-410a has a Global Warming Potential, or GWP, of 2,088. This is about three times the GWP value of R-32, which is 675. A lower GWP value is an indication of higher energy efficiency.

That's why R-32 is considered better than R-410a. Toshiba will continue using R-32 for their split AC units, while they'll stop using R-410a by the first quarter of 2025. This switching of refrigerants aims to have a significant impact on lowering carbon dioxide emissions to the environment.


In this article, we learned what to do when heat mode does not work on a Toshiba air conditioner. We offered solutions, like checking the circuit breaker or relocating the thermostat.

We also shared how to set up the Toshiba remote for their AC units using their app. Remember to check your phone's compatibility.

We also discussed when to turn the heat mode on. In the end, we included what refrigerant the Toshiba air conditioners use.

We hope you enjoyed reading this article. Check out these articles for more information:

How To Install A Toshiba Portable Air Conditioner?

Should I Drain My Toshiba Portable Air Conditioner? [And How To]

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