Diagnostic codes are alphanumeric messages displayed on the indoor unit or remote that help identify specific mechanical or electrical issues. This feature is standard on all Bravo Milano 12,000 BTU Universal Floor/Ceiling units to take the guesswork out of repairs. In a Multi-Zone system, the codes can pinpoint exactly which of the five heads is experiencing an error. You can find a full glossary of these codes in our Other Accessories manuals and support guides. For contractors, these codes allow for much faster service calls, saving the homeowner money on labor. If your unit is showing a "Low Refrigerant" code, checking the flares in your Installation Kits is the best place to start. This smart diagnostic tool is a "built-in technician" that helps you maintain your system with confidence.