Air conditioner not cooling
Ranked from 2,400 repairs on split-system condensers with this symptom. Narrow it below and the ranking recomputes.
Before you start — Kill the power, then discharge the capacitor electrical · refrigerant safety
Pull the disconnect at the outdoor unit AND switch off the breaker. A run capacitor holds a dangerous charge for a long time after the power is off — discharge it across an insulated resistor before you touch the terminals, and never bridge them with a screwdriver. Anything that opens the sealed refrigerant system is EPA-608 licensed work.
Narrow it down
My AC runs but the air isn't cold — what's wrong?
This one usually isn't a part. A clogged filter, a dirty condenser coil, a blocked return or a low refrigerant charge account for most of these — and refrigerant work is EPA-608 licensed, so it is not a DIY repair. Change the filter, wash the outdoor coil, make sure nothing is blocking the returns, and check the line set for ice before you buy anything. If it is still not cold, the charge or the metering device needs a licensed tech.
No part to sell you here
This one is almost always maintenance rather than a failed part — and the checks above are free. Work through them first; if it's still not cold, the charge needs a licensed tech, not a part.
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