The answer to 'my installation won't turn on' is that there are several common causes, including issues with the power supply, thermostat, or the HVAC unit itself. Symptoms may include the system not responding at all, or making unusual noises or smells when attempting to start.
Some potential solutions you can try yourself include checking the circuit breaker, replacing the air filter, and ensuring the thermostat is properly programmed. However, if the issue persists or you're not comfortable troubleshooting it, it's best to call a professional HVAC technician to diagnose and repair the problem.