The answer to 'HVAC repair not cooling' is that there are several common causes, including a refrigerant leak, a faulty compressor, a clogged air filter, or an issue with the thermostat or electrical components. Symptoms may include warm air coming from the vents, the system running constantly, or the unit freezing up.
If the HVAC system is not cooling properly, the first step is to check the air filter and replace it if it is dirty. You can also try adjusting the thermostat to a lower temperature. However, if the issue persists, it is best to call a professional HVAC technician to diagnose and repair the problem. Attempting to service or repair the HVAC system yourself can be dangerous and may void the warranty.