Waterway 1-1/2″ Split Nut with Screws, 400-5491B

The Waterway 400-5491B is a 1-1/2 inch split nut supplied with its screws. It is a compression nut made in two halves, and one side carries the stamp 415-4050. Closed, it measures 2-7/16 inches inside diameter.

Why it splits

A one piece nut has to be slid onto the pipe before the plumbing is assembled. A split nut does not: the two halves close around a pipe that is already fixed in place and the screws draw them together. That is what lets you replace a cracked nut without cutting the pipe apart and rebuilding the joint.

Identifying the right one

This part appears under more than one number. It is catalogued as 400-5491B, shows up as 400-5491, and the nut itself is stamped 415-4050. If any of those numbers matches what you are holding, this is the nut. It is listed with Waterway center discharge pump parts and Waterway pump strainer trap parts. The reliable check is the measurement: 1-1/2 inch plumbing, 2-7/16 inches inside diameter with the halves closed.

Fitting

Bring the halves together evenly and tighten the screws in stages rather than running one down fully first. A nut pulled up crooked will not seal, and over tightening a plastic nut is how the next one cracks.