The answer to 'my system upgrade won't turn on' is that there could be several common causes, such as a tripped circuit breaker, a faulty thermostat, or an issue with the electrical connections. Symptoms may include the system not powering on at all or the display remaining blank.
For simple issues like a tripped breaker, you may be able to reset it yourself. However, for more complex problems with the electrical components or controls, it's best to call a professional HVAC technician. They can properly diagnose the issue and make the necessary repairs or adjustments to get your upgraded system running again.