A technician needs a permanent, leak-free access point after servicing a small sealed refrigerator. Which method is preferred over leaving a bolt-on piercing valve?

解析

A brazed process tube or soldered access fitting gives a durable, leak-free seal, unlike a bolt-on piercing valve whose gasket can degrade. This reduces future refrigerant loss and gives reliable access for later service. Tape or caps on a piercing valve are not acceptable permanent seals.