{"product_id":"pentair-rainbow-3-cap-o-ring-r172009z","title":"Pentair Rainbow O-Ring, Cap \u0026 Extension | Model 300 Series Automatic Feeder | R172009Z","description":"\u003cp\u003eThe Pentair Rainbow O-Ring (R172009Z) is the OEM replacement cap and extension O-ring for the Rainbow Model 300 Series Automatic Chemical Feeders, including the 300-29X Commercial Size Feeder, the 320 In-Line Automatic Feeder, and Rainbow 10\" and 20\" Extension assemblies.\u003c\/p\u003e\n\n\u003cp style=\"background-color: #fff3cd; border: 2px solid #FFEAA7; padding: 15px; border-radius: 5px; margin: 15px 0; color: #856404;\"\u003e\u003cstrong\u003eIMPORTANT: LUBRICATION REQUIRED — SOLD SEPARATELY\u003c\/strong\u003e\u003cbr\u003eAlways lubricate this O-ring with a silicone-based lubricant before installation. We carry the \u003ca href=\"https:\/\/poolaroo.com\/products\/pentairwaterpoolandspainc_r172351\" alt=\"Pentair R172351 Lifeguard Silicone Lubricant\"\u003ePentair R172351 Lifeguard Silicone Lubricant\u003c\/a\u003e — the OEM-matched product for Pentair equipment.\u003c\/p\u003e\n\n\u003cp\u003eThis O-ring seals the cap or extension joint on Rainbow automatic chemical feeders. A failed or degraded O-ring at this connection point allows chlorine or bromine to bypass the seal, leading to chemical leaks and loss of proper feeder pressure. Replacing this O-ring restores a watertight seal at the cap or extension assembly.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; margin: 20px 0; border: 1px solid #ccc;\"\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;\"\u003eR172009Z\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\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;\"\u003eO-Ring, Cap \/ Extension\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\u003ePart Category\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eO-Rings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\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 style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003eCompatible Equipment\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eRainbow Model 300 Series Automatic Feeders; Rainbow 10\" \u0026amp; 20\" Extensions\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003cstrong\u003eBrand \/ Legacy Brand\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eFits Into\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; margin: 20px 0; border: 1px solid #ccc;\"\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 style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eModel 300, 302, 300-19, 300-29 Series\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e300\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eModel 300, 302, 300-19, 300-29 Series\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e302\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eModel 300, 302, 300-19, 300-29 Series\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e300-19\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eModel 300, 302, 300-19, 300-29 Series\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e300-29\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eSanitizer \u0026amp; Water Quality\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e300-29X\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eO-ring, cap\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eSanitizer \u0026amp; Water Quality\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e320\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eO-ring, cap\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #ffffff;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eExtensions \/ Dispensers \/ Flow Indicators\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eR172087\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eO-ring for extension complete models (10 in. Extension Complete)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f8f9fa;\"\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003ePentair (formerly Rainbow)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eExtensions \/ Dispensers \/ Flow Indicators\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eR172283\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eO-ring for extension complete models (20 in. Extension Complete)\u003c\/td\u003e\n\u003c\/tr\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\n\u003ch3\u003ePoolaroo Pro Tip\u003c\/h3\u003e\n\u003cp\u003eBefore threading the cap or extension back onto your Rainbow feeder, apply a thin, even coat of silicone-based lubricant to this O-ring. Silicone lubricant keeps the O-ring pliable and prevents the twisting and micro-tearing that causes early seal failure. The \u003ca href=\"https:\/\/poolaroo.com\/products\/pentairwaterpoolandspainc_r172351\" alt=\"Pentair R172351 Lifeguard Silicone Lubricant\"\u003ePentair R172351 Lifeguard Silicone Lubricant\u003c\/a\u003e is the OEM-matched option for Rainbow equipment. Never use petroleum-based lubricants — they degrade rubber O-rings rapidly and will shorten the life of this seal.\u003c\/p\u003e\n\n\u003c!-- wft:processed:manual:2026-05-01 --\u003e","brand":"Pentair","offers":[{"title":"Default Title","offer_id":51774149951763,"sku":"R172009Z","price":9.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0920\/0687\/5411\/files\/PENR172009Z_0.jpg?v=1747701255","url":"https:\/\/poolaroo.com\/products\/pentair-rainbow-3-cap-o-ring-r172009z","provider":"Poolaroo","version":"1.0","type":"link"}