Why isn’t my Mitsubishi Electric split system working

by | Jun 13, 2023

Mitsubishi Electric split systems are highly regarded for their reliability and energy efficiency. However, like any mechanical system, they may experience issues over time and stop working. Understanding the common reasons why split systems may malfunction is the first step in tackling these issues. In this blog post, we outline the basic components of the split system and how they work together, as well as provide detailed guidance and troubleshooting steps to help you identify the causes of your system’s malfunction.

The Basic Components of a Mitsubishi Electric Split System

Split systems work by dividing the heating and cooling load into two separate units: an indoor unit, which houses the evaporator coil, and an outdoor unit, which houses the compressor, condenser coil, and refrigerant. When the split system is turned on, the refrigerant travels from the outdoor unit to the indoor unit. As it passes through the evaporator coil, the refrigerant extracts heat from the air inside the room, and the cool air is then blown back into the room through the indoor unit.

Common Reasons for Mitsubishi Electric Split System Malfunctions

  1. Dirty Filters: One of the most common reasons for a split system malfunction is a dirty air filter. Over time, filters can accumulate dust, debris, and pollutants, which can restrict airflow and reduce the system’s efficiency. When the system is struggling to draw air in, it can cause the system to overheat or trip the circuit breaker. In severe cases, it can cause the compressor to fail. Regularly cleaning or replacing the filters can prevent this issue.
  2. Refrigerant Leaks: Another frequent cause of split system failure is a refrigerant leak. Refrigerant is crucial to the system’s operation as it absorbs heat from the air to cool the room. When refrigerant leaks out, the system will not be able to cool the room efficiently. Low refrigerant levels can also cause the compressor to work harder than necessary, which can lead to compressor failure. The best course of action is to contact a professional technician to locate and repair the leak.
  3. Electrical Issues: Split systems are complex electrical systems that involve a range of components, including compressors, fans, and motors. If any of these parts malfunction or fail, it can cause the system to stop working altogether. Electrical issues can be caused by a variety of factors such as power surges, faulty wiring, or motors that have worn out. It’s important to enlist the help of a qualified technician to diagnose these issues.
  4. Poor Installation: If the split system was not installed correctly, it can lead to a series of problems such as reduced efficiency, refrigerant leaks, or electrical problems. It’s crucial to ensure that the system is installed by a Mitsubishi Electric Professional who is familiar with the system’s requirements.

Troubleshooting Your Split System

If you suspect that your split system is not working correctly, there are a few things that you can do before calling a technician. First, check to see if the filters are dirty and replace them if necessary. If the filters are clean, check that the thermostat is on and set to the correct temperature. If the system still isn’t working, check the circuit breaker to see if it has tripped. If the circuit breaker is fine, enlist the help of a technician to diagnose the issue.


Mitsubishi Electric split systems are incredibly reliable, energy-efficient cooling and heating systems. However, they may experience issues over time due to dirty air filters, refrigerant leaks, electrical issues, or poor installation. Whenever there is an issue with the split system, it’s essential to contact a professional technician to diagnose and repair the problem to avoid further damage or failure of the system. Regular maintenance and filter changes can help keep your system functioning optimally and avoid issues altogether.

If you require a service of your Mitsubishi Electric split system, contact us today

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