Pentair Black O-Ring | Sta-Rite Posi-Flo II Cartridge Filters | WC9-3 Drain & Suction Covers

Pentair Black O-Ring | Sta-Rite Posi-Flo II Cartridge Filters | WC9-3 Drain & Suction CoversThe Pentair WC9 3 is the OEM replacement black O ring for Sta Rite Posi Flo II pool and spa cartridge filters, keeping the filter housing sealed and operating at full efficiency. IMPORTANT: LUBRICATION REQUIRED SOLD SEPARATELY Always lubricate this O ring with a silicone based lubricant before installation. We carry the Pentair R172351 Lifeguard Silicone Lubricant the OEM matched product for Pentair equipment. This O ring maintains the pressure seal

⚠️ IMPORTANT: Remove Pad Adapter Before Installing

Balance pool water: pH 7

Fitment for IntelliFlo i1 and i2 pumps is confirmed for units manufactured after April 2016

Can be installed during pool installation or as a later addition

For excess foaming problems

Replacing this part restores proper hydraulic distribution and full filtration performance

Built in cup holder

Each pump requires two (2) of these unions — one on the suction side and one on the discharge side

needing only the minimal amount of sanitizer

Nozzle interchangeability allows custom jet placement

It’s an environmentally safe product that isn’t corrosive

The weir is the hinged flap at the skimmer throat that allows surface water and debris to flow into the skimmer basket while preventing collected debris from floating back into the pool when the pump cycles off