Mitsubishi Mini Split AC not Cooling or Blowing Cold Air-10 Solutions

Many people reported that their Mitsubishi mini split AC is not cooling or has stopped blowing cold air. After getting a number of requests, I decided to deal with this issue.

I found some common reasons behind the problem. I would address all the causes and their solutions in this guide. By the end, you will be able to fix your mini split at home.

Mitsubishi Mini Split AC not Cooling or Blowing Cold Air-10 Solutions

The same troubleshooting guide is workable in the opposite situation. For example, in winter if your AC is not producing warm air, apply the hacks mentioned here.

How Does a Mini Split Work?

Before troubleshooting, we should have a brief idea that how a mini-split works. The unit draws warm air from the surroundings in the summer season.

The air then goes to the coils which remove the heat and sends air to the refrigerant liquid. Next, the refrigerant removes the retained heat.

The air goes to the heat pump which releases it into the outside environment. This cycle goes on and your AC produces cold air.

Mini Split not Cooling: Major Reasons

An air conditioner is composed of many parts. Each component has to work efficiently. Otherwise, it will stop blowing cold air. Here are the major and common causes of this issue;

  • The thermostat is running on the wrong settings or is faulty.
  • Air filters are too dirty and clogged thus preventing ventilation.
  • The refrigerant liquid is leaking from somewhere.
  • Condenser coils are clogged due to debris or ice build-up.

Troubleshooting Mitsubishi Mini Split AC

Since you know the causes, it is easy to troubleshoot the AC. The fixes are simple, easy, and quick. Kindly follow the below guidelines correctly.

1. Identify the Error Code

Sometimes, the mini split displays error codes. Note the code and look it up in the user manual or check online. These codes indicate the specific issue. Hence, you can solve the problem easily.

However, there may be no error code but still, the system is not cooling. In this case, you have to apply other fixes.

2. Check Thermostat Settings

Carefully check the thermostat settings. Maybe it is running in winter settings. Therefore, you are getting warm air instead of cold. You need to check the thermostat settings of each air handler (the unit that moves air).

Make sure it is set to “Cool” or “Auto”. Lower the temperature than the room temperature. Moreover, disable the “Fan Mode” as it only circulates air without affecting it. Furthermore, check the thermostat batteries and replace them.

3. Reset Your Mitsubishi Mini Split

A reset can do wonders. Here is how to reset your mini split AC;

  1. Shut down the AC completely. Also, turn OFF the thermostat and isolator.
  2. Unplug the AC from the electric outlet.
  3. Wait 30 seconds and turn ON the isolator.
  4. Wait for 2 minutes before turning ON the whole system on.
  5. Find the reset button on your AC remote. Press this button for a few seconds to reset the air conditioner.

4. Reset the Circuit Breaker

Your Mitsubishi mini split cannot cool if it is not getting the required power. Although it is turned ON yet it will not function fully. So, check the circuit breaker if it is tripped.

Reset the breaker and check the wiring. Moreover, connect the AC to a separate circuit that does not have other heavy appliances. Because it needs high voltage supplied properly.

5. Clean the Air Filters

Air filters in your mini split are exposed directly to dust and dirt. They can be blocked and stop filtering the air. So, the air does not pass through filters and also does not become cool. It is ideal to clean the filters once a month.

If you are not using the split then clean every 3 months. Remove the filters from the AC unit. Then, wash them with running water. Dry them completely before reinstalling. You can also use a vacuum cleaner to remove dirt.

Check the detailed process here.

6. Inspect the Connections

There are 5-7 linking wires between indoor and outdoor units of the air conditioner. If any of the wires are defective, the link will be lost. Therefore, you need to inspect the wiring between the units.

Moreover, check the electrical connections and system of your AC. You can confirm by using a Multimeter. Check the input and output voltage.

7. Check for Refrigerant Leakage

If the refrigerant liquid is leaking, hot air cannot be removed. You can recognize it by some signs. For example, a hissing sound comes from the unit. Moreover, a chemical smell is given by the air handlers or AC units.

Minutely observe the line joining the indoor and outdoor units. Any crack or hole indicates leaking. This problem cannot be fixed at home. So, you have to call a professional technician.

8. Low Refrigerant Level

The refrigerant liquid is very important for cooling. It may be low or has expired. The solution is to fill up the refrigerant again.

But, be sure to consult a certified technician. He will determine the level by checking the pressure.

9. Unblock Condenser Coil

The condenser coil is responsible to remove heat from the air as it comes from the handlers. However, the coils clog due to tiny debris particles. Ice build-up is a very common problem.

Moreover, it can get mold and rust. Hence, air cannot dissipate heat while passing through the coils. Instead, it keeps on circulating without cooling. Please contact a professional to clean the clogged coils.

10. Check the System for Faults

The indoor or outdoor AC unit is faulty if every other thing is fine. The indoor unit has some important components such as a blower motor, condenser, and wires. All these parts need a proper inspection.

Likewise, check the outdoor condenser. Specifically, check the fan motor if it is spinning or not. Moreover, check the compressor and PCB boards.

FAQs About Mitsubishi Mini Split Air Conditioner

Here are some important and common questions that are asked by most users. Take help from them if you have further queries.

Why does my Mitsubishi mini split keep shutting OFF frequently?

Overheating is the most common cause your mini split keeps shutting OFF. It is not receiving proper ventilation. Because the compressor has excessive heat. As a result, the refrigerant level is not maintained.

What to do if my Mitsubishi mini split is not turning ON?

Check the circuit breaker dedicated to your Mitsubishi system. Reset the breaker or replace it if necessary. A tripped circuit breaker indicates a power issue. Hence, you need to call a technician to check the power supply and electrical wiring of your home.

How can I know a low or high Freon/refrigerant level on my mini split?

A low refrigerant level is indicated by unusual noises and ice on coils. While excess Freon causes the system not to turn ON. Moreover, the temperature is unstable and unusual noises are given by the unit.

How often I should recharge Freon/refrigerant in my mini split?

If you care about the maintenance and health of your system, it does not need frequent recharging of Freon. You should recharge the unit once every 2 to 5 years. However, some units can work efficiently even longer than five years.

How long can Mitsubishi Mini Split system last?

Mitsubishi mini split is a popular ductless cooling system. It can last up to 20 years depending on your maintenance habit. It is recommended to clean the air filters every month if the system is running continuously. Moreover, follow other maintenance guidelines to increase the life of your system.

At what temperature should I set my mini split?

In winter, the recommended temperature is 68°F or lower. While for summers, set the temperature at 78°F. It also depends on your home settings, weather, region, and personal preferences.

Does Mitsubishi mini split run all the time?

A mini split is designed to consume a low amount of power. So, it runs all the time and does not turn ON and OFF when the temperature is reached. It is a ductless cooling system known for using low-power modes and efficient temperature maintenance.

You may also like: Fixing the Split AC Compressor if not Turning ON

Concluding Thoughts

Although cooling systems are complex yet you can do the basic troubleshooting at home. Because most of the time, the issue is minor like wrong settings.

Therefore, calling a technician immediately is not a good decision. As you know, he will charge the fee even for a minor problem. Hence, you should learn to deal with everyday electronic appliances.

Our blog aims at making you self-reliant in this regard. Therefore, I suggested basic and easy troubleshooting hacks. These solutions can also be applied to the system if it is not heating in winter.

I am ending this article with the hope that your Mitsubishi mini split AC is now cooling and blowing cold air.

Hi, I'm Noor Alam, Founder of I'm naturally inclined towards modern technical gadgets and Love to solve different problems regarding these gadgets. I will share information with you on how to fix different old devices and how to find the best products. You'll find great help from my research and experience.
Hi, I'm Noor Alam, Founder of I'm naturally inclined towards modern technical gadgets and Love to solve different problems regarding these gadgets. I will share information with you on how to fix different old devices and how to find the best products. You'll find great help from my research and experience.

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