What component should not be disassembled in the field?

Oil buffers should not be disassembled in the field due to the potential hazards and complexities associated with their design and function. These components are critical for providing a smooth and safe ride by absorbing energy during a car's descent and preventing damage to the elevator system. They often contain hydraulic fluids, which can pose environmental and safety risks if improperly handled or if the buffer is disassembled incorrectly. Additionally, the precision engineering involved in oil buffers means that any disassembly could lead to misalignment or malfunction if not reassembled under controlled conditions, necessitating manufacturer support or oversight.

In contrast, the other components listed can often be serviced in the field by trained professionals. For instance, hoistway doors and control panels are designed to be accessible for maintenance and may be adjusted or replaced as necessary. Counterweights, while substantial, can also be managed and adjusted safely by technicians following appropriate protocols. The critical nature of oil buffers, combined with safety concerns and the need for precise functioning, underscores the importance of professional handling and discourages field disassembly.