{"product_id":"pentairwaterpoolandspainc_r172370","title":"Pentair Bottom Locking Flange for Dynamic Filter Series II, III \u0026 IV Filters | R172370","description":"\u003cp\u003eThe Pentair Bottom Locking Flange (R172370) is the OEM replacement flange for the Dynamic Series II, III, and IV cartridge filter lines, including the RTL, RCF, and DFML filter models.\u003c\/p\u003e\n\u003cp\u003eThe bottom locking flange secures the filter tank assembly at its base, maintaining a sealed, pressure-stable connection between the lower tank body and the filter housing. A failed or cracked flange compromises the structural integrity of the filter tank, leading to leaks at the base of the unit. Replacing it with the correct OEM component restores a proper seal and ensures the filter operates within its designed pressure parameters.\u003c\/p\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; margin: 20px 0; border: 1px solid #ccc;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003ePentair Part Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eR172370\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003ePart Name\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eBottom Locking Flange\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003eQuantity Included\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e1 (Each)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid rgb(204, 204, 204); padding: 10px;\"\u003e\u003cstrong\u003eDimensions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid rgb(204, 204, 204); padding: 10px;\"\u003e\n\u003cul\u003e\n\u003cli\u003eTop Outer Diameter: 7-1\/8 inches\u003c\/li\u003e\n\u003cli\u003eBottom Outer Diameter: 8-1\/8 inches\u003c\/li\u003e\n\u003cli\u003eInner Diameter: 6-3\/4 inches\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eFits Into\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; margin: 20px 0; border: 1px solid #ccc;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003eBrand\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003eEquipment Line\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003eModel \/ Part Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003eNotes\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eDynamic Filter Series II \u0026amp; III\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eRTL\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eTop Load In Line Cartridge Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eDynamic Filter Series II \u0026amp; III\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eRCF\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eTop Load In Line Cartridge Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eDynamic Filter Series IV\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eDFML\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eDFML 25C, 25, 35, 50 Lily Pad Skim Filter\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eCompatibility 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.\u003c\/em\u003e\u003c\/p\u003e\n\u003ch3\u003ePro Tip\u003c\/h3\u003e\n\u003cp\u003eBefore ordering, check the part number stamped or molded on your existing flange — Dynamic Series II, III, and IV filters share similar housing designs, and confirming R172370 against the original component is the most reliable way to ensure correct fitment. While the filter is disassembled for this repair, inspect the tank O-rings and any associated sealing surfaces for wear and replace them at the same time to avoid a repeat service call.\u003c\/p\u003e\n\u003c!-- wft:processed:manual:2026-04-06 --\u003e","brand":"Pentair","offers":[{"title":"Default Title","offer_id":53971960660243,"sku":"R172370","price":19.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0920\/0687\/5411\/files\/pentair-bottom-locking-flange-for-dynamic-filter-series-ii-iii-iv-filters-r172370.webp?v=1787784216","url":"https:\/\/poolaroo.com\/products\/pentairwaterpoolandspainc_r172370","provider":"Poolaroo","version":"1.0","type":"link"}