1. What is the documented operating range?
Request the stated voltage and frequency range for the exact indoor and outdoor unit combination. Do not assume one value applies to every capacity or inverter platform.
2. What happens near the limits?
Clarify whether the unit continues cooling, reduces output, displays a fault or shuts down. The practical behaviour matters more than a large voltage range printed in a headline.
3. How does the unit recover?
Ask about delay protection and automatic restart after a power interruption. For distributor and project sales, document whether settings are retained and whether restart behaviour can be configured.
4. Which protections are included?
Confirm the protection method and whether an external stabilizer or surge-protection device is still recommended for the project. Site wiring and installation quality remain part of the system.
5. What is covered by warranty?
Make sure the proposed operating conditions are consistent with the model documentation and warranty terms. Include the destination supply conditions in the purchase specification instead of relying on a marketing phrase.