The answer to 'ductless system not turning on' is that there could be several common causes, including a tripped circuit breaker, a faulty thermostat, or issues with the outdoor unit. Symptoms may include the system not powering on at all or the indoor unit not responding to the thermostat controls.
In many cases, the solution may be as simple as resetting a tripped circuit breaker or replacing the thermostat batteries. However, if the issue persists or you're unsure of the root cause, it's best to call in a professional HVAC technician to diagnose and repair the problem. Ductless systems have complex electrical and refrigerant components that require specialized knowledge and tools to service properly.