Pentair Lid O-Ring, 5-3/4" ID

The Pentair 350013Z is the strainer lid o-ring for the Challenger, the newer style WhisperFlo, the IntelliFlo and select EQ Series commercial pumps. It measures 5-3/4 in. across the inside with a 1/4 in. cord, and it is the genuine Pentair part rather than a generic ring cut to a nearby size.

Why it matters

The lid o-ring is the only thing keeping air out at the top of the strainer pot. When it hardens, flattens or splits, the pump pulls air past the lid, the basket fills with bubbles and the pump loses prime or runs noisy. It is one of the cheapest parts on the pad and one of the most common causes of a pump that will not hold water.

Replacing it

Turn the pump off, open the lid, lift the old ring out of its groove and clean the groove. Coat the new ring lightly with a silicone based o-ring lubricant, seat it evenly and close the lid. If the pump still draws air afterward, look at the suction side unions and the drain plugs next.