In hydronics, what fitting is used to transition from an 8 inch NPS to a 12 inch NPS suction piping?

In hydronics, when transitioning from a larger diameter pipe to a smaller diameter pipe, an eccentric reducer is often used. The eccentric reducer allows for a smooth, gradual change in pipe diameter, which is essential in suction piping applications to avoid abrupt changes that could lead to turbulence and pressure losses.

The version of the eccentric reducer that is flat on top is specifically designed to maintain a level flow path. This helps in preventing air from getting trapped in the piping system, especially in horizontal applications where air pockets can lead to inefficiencies and potential operational issues.

Choosing this fitting ensures that the transition maintains a constant elevation, which is crucial in hydronic systems where the flow dynamics can impact the overall efficiency and performance of the system. In contrast, other fittings such as elbows do not provide the necessary gradual transition, and couplings do not change the diameter of the pipes at all. A concentric reducer would change the pipe diameter in a way that could introduce turbulence, which is not desired in suction lines.