There could be a number of issues, the most likely is overheating of the external heat exchange or internal filter needs cleaning. Can you advise the model number of Air Con unit you have?
Most Aermec displays have an alarm button you can press to show the alarm fault codes, are you able to access any of the fault codes, or advise what the display shows when you press the alarm button?
There should be a remote control panel for the unit, which will allow an error code to be identified, and set the min\max temperatures etc.
However in the absence of the remote, are you able to attach a picture of the control panel on here, or on the website here, and post the link as a message?
Good afternoon, I havent heard back from you I just wanted to follow up to see if you required any further assistance?