The answer to 'air conditioner not working' is that there are several common causes, including a tripped circuit breaker, a dirty air filter, a refrigerant leak, or a faulty compressor. Symptoms may include the unit not turning on, poor cooling performance, or strange noises or smells. Some basic troubleshooting and maintenance steps can often resolve the issue, but more complex problems may require a professional HVAC technician.
If your air conditioner is not working, first check the circuit breaker and reset it if it has tripped. Then, inspect the air filter and replace it if it is dirty. You can also try cleaning the outdoor condenser unit if it is obstructed by debris. If those steps don't fix the problem, the issue may be a refrigerant leak or a faulty compressor, which will require a professional HVAC technician to diagnose and repair.