Not Cooling
Mitsubishi Electric Air Conditioner
Severity:What Does This Error Mean?
A Mitsubishi Electric AC that runs but does not cool is most often caused by a dirty air filter, Fan Only mode selected on the remote, or the outdoor unit being unable to expel heat. Clean the filter and confirm Cool mode is selected on the remote.
Affected Models
- Mitsubishi Electric MSZ Series
- Mitsubishi Electric SRK Series
- Mitsubishi Electric MSZAP Series
- Mitsubishi Electric MSZEF Series
Common Causes
- Dirty air filter blocking airflow
- Remote set to Fan mode instead of Cool mode
- Outdoor unit heat exchanger dirty or obstructed
- Refrigerant low due to a leak
- Outdoor unit fan not spinning
How to Fix It
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Confirm Cool mode is selected.
On the Mitsubishi Electric remote, press the Mode button until the snowflake (Cool) icon appears on the display. The unit will run but produce no cooling in Fan, Dry, or Heat modes. Also confirm the set temperature is lower than the room temperature.
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Clean the indoor air filters.
Open the front panel of the indoor unit — it usually hinges upward. Slide out the mesh filters and wash under running water. Allow to dry completely before reinserting. Mitsubishi Electric recommends cleaning filters every 2 weeks during regular operation.
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Clean the indoor unit louvres and vents.
Use a soft cloth to wipe dust from the horizontal and vertical air direction louvres. Heavy dust build-up on the louvres reduces outflow and makes the unit appear to cool less effectively.
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Check the outdoor unit.
Inspect the outdoor unit and confirm the fan is spinning and warm air is being exhausted from the top. Look for ice on the refrigerant lines or outdoor coil — frosting indicates low refrigerant. Ensure there are at least 30 cm of clearance around all sides of the outdoor unit.
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Book a service if problems persist.
If the above steps do not restore cooling, the system requires professional diagnosis. Common causes at this stage include a refrigerant leak, a failing expansion valve, or a dirty outdoor heat exchanger that requires chemical cleaning.
When to Call a Professional
If cleaning the filter and checking the outdoor unit does not restore cooling, and the outdoor unit coil is iced or the refrigerant lines are frosting, refrigerant has likely leaked. Only a licensed technician can diagnose and repair a refrigerant leak.