Waterway Pump Union Assembly with O-Ring, 2″ Nut x 2″ Slip, 400-5670

The Waterway 400-5670 is a pump union assembly with o-ring, 2 in. union nut on one side and 2 in. slip socket on the other. It is the genuine Waterway part.

Why a union is there

A union is the joint that lets equipment come out of a plumbing run. The nut side threads onto the pump port and the slip side is cemented to the pipe, so when the pump has to come out for service or replacement, the nut backs off by hand and the pump lifts away. Without one, that same job means cutting pipe and repiping afterwards.

When to replace it

Unions leak for two reasons. Either the o-ring has taken a set and no longer fills the seat, or the nut has been cross threaded or cracked, usually by someone reaching for a wrench. The o-ring is the first thing to check. If the nut or the seating face is damaged, the whole assembly needs to go.

Making it up

Seat the o-ring clean and dry of grit, then run the nut down by hand until it is snug. That is as far as it needs to go. If it still weeps at hand tight, the o-ring or the seat is the problem, and more force will only crack the plastic.