Isolation valves are used to "lock" refrigerant inside the outdoor unit or a specific part of the system during maintenance. On a Ductless Mini Split, these are the brass service valves where the Line Set connects. They allow a technician to perform repairs without losing the entire gas charge. Our Cooper&Hunter units feature high-quality valves that are designed for years of leak-free service. You must use an Allen wrench to open these valves after the Evacuation Process is complete. For Multi-Zone systems, each port has its own set of valves. Proper use of these valves is essential for a safe and successful startup. You can find technical guidance on these connections in the Technical Data section.