The code indication changes as shown below, and notifies with a long beep. Wall Mounted AC Inverter Unit Error Codes for G18 and GS02 – Inverter Y Models Netware 3C / SLM 9 – Inverter Y Models (Except 5WMY-J/JR) Sequential Controller (SQ LCD) – SB & RT Multi Compressors Error Diagnosis by Wired Controller (MC301)