Which plumbing fitting is primarily used to change the direction of water flow?

The plumbing fitting that is primarily designed to change the direction of water flow is the elbow. Elbows are specifically manufactured to enable a change in direction, typically at angles of 90 or 45 degrees. This functionality is crucial in plumbing systems, allowing for the efficient routing of pipes around obstacles or between different fixtures in both residential and commercial settings.

In contrast, connectors are used to join two sections of pipe together without changing the flow direction, while couplings serve a similar purpose by connecting two pipes but are also not intended for altering the direction of flow. Valves, on the other hand, are utilized to control the flow of water rather than change its direction, making them integral for regulating water supply but not for rerouting water through a system.