Waterway 2″ Heater O-Ring/Gasket, 711-4030

The Waterway 711-4030 is the 2 inch heater o-ring gasket. It measures 2-15/16 inch across the outside and 2-1/8 inch across the inside.

The two thickness figures

This ring is made with a rib rather than as a plain flat gasket, which is why the specification carries two thicknesses. The flat section is 3/32 inch. Measured across the whole ring, including the o-ring extension, it is 3/16 inch. If you are comparing against a ring you already have in hand, measure the flat part to make the match.

When to change it

A union gasket is cheap and the leak it causes is not. Once the old ring has taken a set, gone hard or split, it will not seal again no matter how much the union is tightened, so it is worth replacing whenever the connection is opened.