Mistral mss 1.0kw unit - When switched on the
If the indoor unit blower is running and the outdoor unit fan is turning, you will need to make sure that the compressor itself is actually running and that it is not just the outdoor fan that is turning.
Get close and listen to the end of the unit were the compressor is located, also carefully feel the two copper lines, where they connect to the outdoor unit, they can be very hot - if working properly, so be careful.
There is no reset button that is easy to get to, the limits are usually auto resets, I would hazard a guess that the system is low on refrigerant and will require a HVAC tech.
But before that, make sure that the coils / fins on the outdoor unit are clean and not plugged with leaves, grass, cottonwood, ect.
You can turn power off to the unit and carefully wash the coil out with a garden hose, do not use a nozzle, as the higher water pressure can bent the fins.
As the water runs thru and drains off of the coil, watch and see if it is very dirty, rinse till the water is clean.
Restore power to the unit and try it, If it still does not work, the unit might be low on freon or the safeties might have been already damaged.
Once the unit is repaired, in the future make sure and keep the coil rinsed and free of any blockages.
Paul Gibson