The oil-return cycle is an automated logic routine that ensures the compressor's lubricant is pulled back from the long line sets periodically. This is vital for Multi-Zone systems where some heads may be up to 100 feet away from the condenser. Every Bravo Milano 12,000 BTU unit is programmed to run this cycle every few hours of operation. To assist the system, always ensure your line sets are sloped correctly as outlined in our Installation Kits. If your outdoor unit is on a Ground Stand, the oil can return more naturally via gravity in many layouts. We also offer Other Accessories to help professionals measure the total oil levels in larger systems. This invisible maintenance routine is the key to preventing "dry" starts and ensuring a long compressor life.