The answer to 'mini split blowing hot air' is that there are several common causes, including a refrigerant leak, a problem with the compressor, or an issue with the reversing valve. Symptoms may include the air conditioning not cooling properly, the unit making unusual noises, or the air blowing hot even when set to cool.
In many cases, the solution may require professional HVAC service. Attempting to diagnose and repair a mini split system without proper training and equipment can be dangerous and may even void the warranty. It's generally best to call a licensed HVAC technician to inspect the system, identify the root cause, and make the necessary repairs.