The answer to 'HVAC repair not working' is that there could be several common causes, including a faulty thermostat, clogged air filters, issues with the compressor or blower motor, refrigerant leaks, or electrical problems. Symptoms may include the system not turning on, poor airflow, inconsistent temperatures, or strange noises.
For minor issues, you may be able to troubleshoot and fix the problem yourself, such as replacing air filters or checking the thermostat. However, for more complex problems, it's best to call in a professional HVAC technician who can properly diagnose and repair the issue to ensure your system is working safely and efficiently.