{"product_id":"pentairwaterpoolandspainc_77707-0119","title":"Pentair Coil\/Tubesheet Sealing O-Ring Kit | Max-E-Therm 400 \u0026 MasterTemp 400 Heaters | 77707-0119","description":"\u003cp\u003eThe Pentair Coil\/Tubesheet Sealing O-Ring Kit (77707-0119) is the OEM replacement O-ring set for the water system coil and tubesheet sealing points in the Max-E-Therm 400 and MasterTemp 400 series heaters. This kit contains 12 O-rings — the complete set required to service all coil\/tubesheet sealing positions in the 400-model heat exchanger assembly.\u003c\/p\u003e\n\u003cp style=\"background-color: #fff3cd; border: 2px solid #FFEAA7; padding: 15px; border-radius: 5px; margin: 15px 0; color: #856404;\"\u003e\u003cstrong\u003e⚠️ IMPORTANT: KIT OF 12 O-RINGS — NOT A SINGLE PIECE\u003c\/strong\u003e\u003cbr\u003eThis listing is a kit of 12 O-rings. All 12 are required to fully service the coil\/tubesheet sealing positions in the 400-model heater water system. Do not order a single unit expecting to service the full assembly.\u003c\/p\u003e\n\u003cp style=\"background-color: #fff3cd; border: 2px solid #FFEAA7; padding: 15px; border-radius: 5px; margin: 15px 0; color: #856404;\"\u003e\u003cstrong\u003e⚠️ IMPORTANT: HEATER COMPONENT — PROFESSIONAL INSTALLATION REQUIRED\u003c\/strong\u003e\u003cbr\u003eGas and electrical heater components must be serviced by a licensed pool professional or qualified HVAC technician. Do not attempt to service gas or high-voltage components without proper certification.\u003c\/p\u003e\n\u003cp\u003eThese O-rings seal the coil and tubesheet interface within the heater's water system heat exchanger. When these seals degrade, water can bypass the intended flow path or leak internally, reducing heating efficiency and potentially causing damage to the heat exchanger assembly. Replacing the full set of 12 O-rings restores a proper water-tight seal across all coil\/tubesheet contact points. Match the part number 77707-0119 against your existing parts or your heater's service documentation before ordering.\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;\"\u003e77707-0119\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;\"\u003eCoil\/Tubesheet Sealing O-Ring Kit\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;\"\u003eKit of 12 O-rings\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;\"\u003eMasterTemp 400 Series\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e400NA\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e12 O-rings included; for Models 400NA, 400LP. Kit quantity = 1 (all 12 O-rings included).\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;\"\u003eMasterTemp 400 Series\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e400LP\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003e12 O-rings included; for Models 400NA, 400LP. Kit quantity = 1 (all 12 O-rings included).\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;\"\u003eMax-E-Therm 400 (NA\/LP Series)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eMAX-E-THERM-400-NA\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eCoil\/Tubesheet Sealing O-Ring Kit for 400 Model. 12 O-rings per kit.\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;\"\u003eMax-E-Therm 400 (HD Series)\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eMAX-E-THERM-400-HD\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #ccc; padding: 10px;\"\u003eCoil\/Tubesheet Sealing O-Ring Kit for 400 Model. 12 O-rings per kit.\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\u003eWhen servicing the heat exchanger, replace the full set of 12 O-rings — not just the ones showing visible wear. Partial replacement leaves aged seals in place that are likely to fail shortly after reassembly, requiring a repeat disassembly. Before installation, apply a thin coat of \u003ca href=\"https:\/\/poolaroo.com\/products\/pentairwaterpoolandspainc_r172351\" alt=\"Pentair R172351 Lifeguard Silicone Lubricant\"\u003ePentair R172351 Lifeguard® Silicone Lubricant\u003c\/a\u003e to each O-ring to help seat it evenly, prevent tearing during assembly, and extend service life. Never use petroleum-based lubricants — they will degrade rubber O-rings and accelerate seal failure.\u003c\/p\u003e\n\u003c!-- wft:processed:manual:2026-04-06 --\u003e","brand":"Pentair","offers":[{"title":"Default Title","offer_id":53980251554067,"sku":"77707-0119","price":62.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0920\/0687\/5411\/files\/pentair-coil-tubesheet-sealing-o-ring-kit-max-e-therm-400-mastertemp-400-heaters-77707-0119.webp?v=1779916834","url":"https:\/\/poolaroo.com\/products\/pentairwaterpoolandspainc_77707-0119","provider":"Poolaroo","version":"1.0","type":"link"}