Industrial Maintenance Technician Practice Test 2025 - Free Maintenance Technician Practice Questions and Study Guide

A reducing coupling serves the essential function of connecting pipes of different diameters. This type of fitting allows for a smooth transition between two sections of piping that may not be the same size, which is common in various plumbing and piping applications. By using a reducing coupling, you can effectively manage changes in pipe dimensions while maintaining the flow of fluid through the system.

In practical scenarios, this is particularly important in systems where you might need to adapt to existing infrastructure, accommodate varying flow rates, or follow specifications that require different pipe sizes. Utilizing a reducing coupling ensures that the connection is secure and that the flow dynamics remain efficient and functional.

In contrast, other options like stopping water flow, creating a bend, or increasing water pressure pertain to different types of fittings or devices, which do not serve the primary purpose of connecting dissimilar pipe sizes.