A mini-split that has stopped cooling but is still obviously running is one of the most common calls of the summer, and the causes fall into a short list.
Start with the filters, because they are behind roughly half of it and they are the one item on this list you can deal with yourself. The mesh filters behind the front cover of the indoor head clog with dust, and a clogged filter starves the coil of airflow. The unit then does exactly what you are seeing: it runs, the fan turns, and the room does not get cold. Lift the cover, slide the filters out, rinse them, let them dry properly, put them back. Ten minutes, no tools, and it is worth doing every few weeks in heavy use.
If the filters were clean, look at the outdoor unit. It needs airflow across its coil to dump heat, and it frequently does not have it — a bag against the side, a shrub grown into it, a coil packed with dust and pollen, or something stacked in front of it. On a hot day a smothered outdoor unit cannot reject heat, so the whole system slowly gives up.
Third is refrigerant charge, and this is where it stops being a homeowner job. A mini-split is a sealed system: it does not consume refrigerant, so if the charge is low, it leaked. That means the honest fix is finding the leak and repairing it, then weighing in a correct charge — not topping it up. A unit that gets topped up every summer is a unit with an unrepaired leak, and you are buying refrigerant on a schedule. A classic sign is ice forming on the indoor coil or the line, which is worth mentioning when you call.
Fourth is the condensate drain, which usually shows up as a different symptom: water dripping down the wall under the head, or the unit shutting itself off. A mini-split pulls a surprising amount of water out of the air, and that has to run away somewhere. When the drain line blocks with dust and algae the tray fills, and better units then stop rather than flood the wall. Cheaper ones flood the wall.
Beyond that you are into fan motors, control boards, sensors and fault codes — and mini-splits are good at fault codes. If the head is blinking a pattern or showing a code on the display, write it down before you call. It genuinely shortens the visit.
One last thing that is not a fault at all. A mini-split that was oversized for its room will cool it fast, satisfy the thermostat, shut off before it has removed any real humidity, and leave the room cold and clammy. Nothing is broken. It was sized wrong at installation, which is why sizing gets so much attention on the mini-split page of this site.
Talk to Xpress HVAC
Tell us what the system is doing. We will tell you plainly what it needs — and if it has failed right now, we are open.