Pentair 355331Z Diffuser O-Ring Part Number: 355331Z Description Genuine Pentair diffuser O-ring designed to seal the diffuser component of select Pentair pool pumps, preventing leaks and maintaining optimal performance of the pump's hydraulic path. Compatibility & Fitment Designed for Pentair Challenger High Flow and High Pressure inground pump models. Also fits the Pentair WaterFall specialty pump series. Recommended for use when the diffuser is removed for service or when you observe seepage or loss of pressure at the diffuser joint. Features & Specifications Precision molded sealing ring sized for the diffuser groove (approximately 3″ inside diameter, ¼″ cross-section). Constructed of pool-rated elastomeric material compatible with chlorinated and saltwater environments. OEM Pentair part ensuring correct fit and performance versus generic substitutes. Installation Notes Shut off power to the pump and relieve system pressure. Remove the pump housing and extract the diffuser. Remove the old O-ring, clean the groove and diffuser surface, install the 355331Z O-ring ensuring it sits flat and undamaged, re-install the diffuser and secure per manufacturer torque specifications. After restart, monitor the pump for any signs of leakage or loss of prime. Maintenance Tip Inspect the diffuser O-ring during routine pump service (e.g., housing re-assembly or annual inspection). If the O-ring appears flattened, cracked or shows signs of chemical degradation, replace it with the 355331Z to ensure long-term sealing integrity and avoid costly pump or system damage.
