The answer to 'system upgrade not working' is that there can be several common causes, including improper installation, incompatible components, or issues with the electrical system. Symptoms may include the system not turning on, poor airflow, or inconsistent temperatures throughout the home. To troubleshoot and resolve the issue, it's important to first identify the root cause.
If you're comfortable working with HVAC systems, you can try some basic DIY troubleshooting steps, such as checking electrical connections, verifying the thermostat settings, and inspecting the air filters. However, for more complex issues or if you're unsure of the problem, it's best to call a professional HVAC technician. They have the expertise and tools to properly diagnose and fix the issue, ensuring the system is working safely and efficiently.