Flo Control 1720C15 Check Valve Swing 1.5" Slip True Union If the O-ring is swollen

If the O-ring is swollen or cracked it can cause your pump to suck air and spit air back into the pool through inlets and it must be replaced

Val-Pak V38221 Bottom Manifold Gasket

Hayward SPX0722P2 Ball Seal for Trimline Ball Valves Set of 2

Waterway 602-4347 1" Notched Top Access Diverter Valve Cap - Gray

Flo Control 1720C15 Check Valve Swing 1.5" Slip True Union If the O-ring is swollenPVC True Union Swing Check Valve, Clear pvc body, No Valterra available, 1. 5"slip x slip. Features: Air Blower Check Valve Type Swing Plumbing Connection Size "A" 1. 5" Plumbing Connection Type "A" Slip with Union Plumbing Connection Size "B" 1. 5" Plumbing Connection Type "B" Slip with Union Spring Tension 0. 5 lb Check Valve Application Air, Water Air Blower Fitting Type union check valve