The Pentair Lock Ring (R172214) is the OEM replacement lock ring for the Pentair Dynamic Filter Series II & III cartridge filters, Pentair Leaf Trap models 179 and 179C, and Pentair High-Capacity Automatic Feeders (HC-3315, HC-3330, HC-3340). The lock ring threads onto the housing canister and holds the lid or body sections together under operating pressure. A cracked, stripped, or deformed lock ring allows the housing to separate during operation, interrupting filtration or chemical feed and risking equipment damage. Replace when threads show visible wear, when the ring no longer seats firmly under hand-tightening, or when the housing leaks despite a fresh O-ring. Specifications Pentair Part Number R172214 Part Name Lock Ring Quantity Included 1 Fits Into Brand Equipment Line Model / Part Number Notes Pentair Dynamic Filter Series II & III RTL Top Load In Line Cartridge Filter, 1-1/2 in. & 2 in. High Flow Pentair Dynamic Filter Series II & III RCF Top Load In Line Cartridge Filter, 1-1/2 in. & 2 in. High Flow Pentair Leaf Traps / Leaf Eaters 179 Lock ring for Model 179/179C Pentair Leaf Traps / Leaf Eaters 179C Lock ring for Model 179/179C Pentair Leaf Traps / Leaf Eaters 360476 2.2 L Leaf Trap — For Model 179/179C Pentair High-Capacity Automatic Feeders HC-3315 — Pentair High-Capacity Automatic Feeders HC-3330 — Pentair High-Capacity Automatic Feeders HC-3340 — Compatibility is based on Pentair parts documentation and available OEM records. This is not an exhaustive list. For certainty, verify the part number in your equipment's manual or on the original part itself before ordering. Poolaroo Pro Tip Before removing the old lock ring, note the thread direction — some Pentair housings use a reverse-thread ring that loosens clockwise. When installing the replacement, hand-tighten only; over-tightening with a tool can crack the ring or distort the housing threads. If threads on the housing body itself are stripped, the housing will need replacement regardless of the new lock ring condition. This lock ring spans three distinct Pentair equipment families that share a common housing thread design — always confirm R172214 against the part number molded into your existing ring or your equipment's exploded parts diagram before ordering.