What type of maintenance is referred to as "preventative maintenance"?

Preventative maintenance refers to the routine checks and servicing conducted on a system, like an elevator, to ensure it continues to operate effectively and to prevent potential malfunctions before they happen. This type of maintenance is proactive, involving scheduled inspections, lubrications, adjustments, and parts replacements based on the manufacturer's recommendations or usage patterns rather than waiting for problems to arise.

By performing preventative maintenance, elevator operators can identify and address potential issues at an early stage, reducing downtime and the likelihood of costly repairs or disruptions in service. This approach not only enhances the safety and reliability of the elevator but also extends its operational life.

The other options describe maintenance practices that are reactive or less comprehensive. Immediate repairs focus on fixing issues after they occur, which does not prevent future problems. Visual inspections alone may not be sufficient to identify deeper issues that could lead to malfunctions. Post-installation adjustments might be part of the maintenance cycle but do not encompass the ongoing and systematic nature of preventative care. Thus, the emphasis on regular and thorough servicing defines preventative maintenance accurately.