Causes and Fixes When Mini Split Not Blowing Cold or Hot Air

By | January 29, 2024

Causes When Mini Split Not Blowing Cold Air
If you have a mini split that is no longer blowing out cold or hot air, there can be several causes and fixes.

Mini split units are usually very reliable and last many years for cooling and heating space.

As with anything, there can be issues at times with the problem needs to be narrowed down.

The first thing to do with any mini split unit not cooling is to see if it has any error codes that point to the issue.
How To Fix a Mini Split E1 Error Code
If the inside unit has an error code, the code can be looked up in the manual or online to see what part of the system has failed.

Sometimes no error code displays, but the system is not working correctly, in which case more troubleshooting will need to be done.

9 Most Common Causes When Mini Split Not Blowing Cold or Hot Air

  1. Temperature Not Set Correctly on Remote
  2. Temperature not Set Correctly or not Set on Cool
    A common problem is the unit is not set to a low enough temperature or not set on cooling mode.

    The remote control usually sets the temperature along with the heating or cooling mode.

    Each system works differently, but be sure to check the remote is set to cool and set to a low enough temperature so the unit will startup.

  3. Indoor Filter Dirty or Clogged
  4. Indoor Unit Dirty Clogged
    The inside unit can become clogged with dirt and debris, which will stop them from working.

    There are usually two filters that filter out any contaminants which can be checked to see if they are clogged up.

    In some cases, the inside condenser can become clogged up with debris and need a full cleaning.

  5. Blown Breaker or Faulty AC Electrical
  6. Blown Breaker or Faulty AC Electrical
    The unit needs power to operate, and the AC electrical should be checked.

    The breaker and disconnect can be checked to be sure they are working correctly.

    A multi-meter can also be used to measure the power at the outside unit terminal leads where the power goes into the unit.

  7. Outside Condenser Fan Motor Bad or Blocked
  8. Outside Condenser Fan Motor Bad or Blocked
    The outside condensing unit has a large fan that spins and blows air past the condenser fins.

    If the fan becomes blocked or has an issue, the unit will not be able to work properly and cool.

    Check the outdoor unit is not blocked and that air can freely blow in and out of the unit.

    The fan should also be spinning, and if not, there is likely an issue.

  9. Line Set Leak

  10. The line set is two copper lines that run between the indoor and outdoor units which carry refrigerant.

    The refrigerant cycle through the system carries heat away or in, depending on the mode.

    If the system has a leak, the refrigerant will become low, and the unit will no longer work properly.

  11. Low on Refrigerant
  12. Low on Refrigerant
    A system low on refrigerant will not send out cool air.

    This is usually caused by a leaky line set, such as a bad flare, or pinhole leak.

    While the line set is the usual cause, the indoor or outdoor unit can also leak and be an issue.

    If the system is low on refrigerant, the leak will need to be found and the correct amount of refrigerant added in, which is done by weight.

  13. Communication Line Wiring
  14. Communication Line Wiring
    The communication wires run between the inside and the outside units.

    There are usually 5-7 wires which allow the two units to communicate and bring in power for the indoor unit.

    If one of the connections is bad, the system will have a problem and usually sends out an error code.

    While the main PCB usually sends out an error, a faulty communication wire can cause strange issues with no codes at times.

  15. Fault Indoor Unit
  16. Fault Indoor Air Handler
    The indoor unit may be having issues and should be checked.

    The main indoor components are the circuit boards, blower motor, wiring, clogged condenser, or leaky unit.

    Often when an the indoor unit has an issue an error code will display.

  17. Faulty Outside Condenser
  18. Outside Condenser Fan Motor Bad or Blocked
    The outdoor condenser should also be checked for any issues.

    The condensing fan motor can be tested and checked to see if it is spinning.

    An outdoor unit also contains the compressor and PCB boards.

    If there is a malfunction an error code will usually display on the indoor unit.

Having a mini split that stops blowing cold air can no doubt be very annoying, especially on a hot day.

Common issues include the unit not set on cooling mode, Leaking refrigerant, low refrigerant, clogged indoor unit, and more.

Often an error code is displayed on a unit when it stops cooling, but in some cases, no code displays.

If a code does display, it will help to point to the problem and the bad component.

Each part of the mini split will need to be examined for what the potential cause and fix will be.

While mini split units are not as big as traditional HVAC units, they still work the same with refrigerants and different pressures flowing through a closed system.

Have you had issues with a mini split not cooling? Let us know in the comments below.

Category: Mini split heating and cooling air conditioner heat pump systems

About Aaron H. Benetti

Aaron H. Benetti an HVAC technician who has worked in the field since 1991. He began his career as an HVAC installer and later began doing troubleshooting and repairs. Around 2010, he began to write books on HVAC topics, mainly tutorials and how-to information. Currently, Aaron works as an HVAC tech and also writes many articles and posts for websites as well as books and videos on HVAC topics.

2 thoughts on “Causes and Fixes When Mini Split Not Blowing Cold or Hot Air

  1. Doc

    unit NOT HEATING, code “FY” on unit display, no error code manual, no available research on “FY” either

  2. elvis garcia

    I have premium levella split it has been working for one year and begin to fail some time works perfect and stop to cooling and blow hot air , I reset the power cable and control and sometimes begin to work again other time no


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