{"product_id":"pentair-mastertemp-digital-iid-asme-natural-gas-low-nox-heater-400k-btu","title":"Pentair MasterTemp® Digital IID ASME Natural Gas Low NOx Pool \u0026 Spa Heater 400K BTU","description":"\u003cstyle\u003e\n.product-tabs__tab-content *,\n.rte *,\n.product-description *,\n.tabs-content * {\n  border-left: none !important;\n  box-shadow: none !important;\n}\n.product-tabs__tab-content details,\n.rte details,\n.product-description details,\n.tabs-content details {\n  border-left: none !important;\n  border-right: none !important;\n  border-top: none !important;\n}\n.product-tabs__tab-content summary,\n.rte summary,\n.product-description summary,\n.tabs-content summary {\n  border: none !important;\n  outline: none !important;\n  box-shadow: none !important;\n}\n\u003c\/style\u003e\n\u003cdiv class=\"cf-product\"\u003e\n\n  \u003cdiv class=\"cf-trust-strip\" style=\"display:flex; flex-wrap:wrap; gap:16px; justify-content:space-around; padding:16px; background:#f7f9fb; border-radius:8px; margin-bottom:24px; text-align:center; font-size:13px; color:#1a2b3b;\"\u003e\n    \u003cdiv\u003e\u003cstrong\u003e✓ Authorized Dealer\u003c\/strong\u003e\u003c\/div\u003e\n    \u003cdiv\u003e\u003cstrong\u003e✓ Free Shipping\u003c\/strong\u003e\u003c\/div\u003e\n    \u003cdiv\u003e\u003cstrong\u003e✓ Manufacturer Warranty\u003c\/strong\u003e\u003c\/div\u003e\n    \u003cdiv\u003e\u003cstrong\u003e✓ Expert Support\u003c\/strong\u003e\u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cp style=\"font-size:17px; line-height:1.6;\"\u003eThe \u003cstrong\u003ePentair MasterTemp® Digital IID ASME Natural Gas Low NOx Pool \u0026amp; Spa Heater 400K BTU\u003c\/strong\u003e delivers all the efficiency, convenience, and reliability of the MasterTemp platform — with ASME-certified construction required for many commercial pool installations. User-friendly indicator lights make system operation and monitoring a snap, and the compact design and super-quiet operation won't intrude on poolside leisure.\u003c\/p\u003e\n\n  \u003cp\u003eBuilt by Pentair with ASME certification, Digital IID ignition, Low NOx emissions, and 400,000 BTU natural gas output in the compact 23-inch MasterTemp cabinet. Backed by a 2-year warranty.\u003c\/p\u003e\n\n  \u003cp\u003e\u003cstrong\u003e⚠️ Professional Installation Required.\u003c\/strong\u003e Pool heater installation involves gas line connections and electrical wiring. Always use a licensed contractor to ensure safety, code compliance, and warranty validity.\u003c\/p\u003e\n\n  \u003ch2 style=\"margin-top:32px; font-size:24px;\"\u003eKey Features\u003c\/h2\u003e\n  \u003cdiv style=\"display:grid; grid-template-columns:repeat(auto-fit, minmax(260px, 1fr)); gap:20px; margin-top:16px;\"\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eASME Certified Construction\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eBuilt to the most rigorous pressure vessel standards — required for many commercial pool installations.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003e400,000 BTU Natural Gas\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eMaximum-capacity heating in the ASME-rated MasterTemp platform.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eDigital IID Ignition\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eIntermittent Ignition Device — reliable electronic ignition without a standing pilot light.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eLow NOx Certified\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eMeets low emissions standards — green certified.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eDigital Indicator Lights\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eUser-friendly indicator lights for simple operation and monitoring.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eCompact, Quiet Design\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eSame 23-inch wide MasterTemp cabinet — super-quiet operation.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eIndoor and Outdoor Rated\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eSuitable for both indoor and outdoor pool and spa installations.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003e2-Year Warranty\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003ePentair warranty coverage.\u003c\/p\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003ch2 style=\"margin-top:32px; font-size:24px;\"\u003eWho It's For\u003c\/h2\u003e\n  \u003cul style=\"font-size:15px; line-height:1.7;\"\u003e\n    \u003cli\u003eCommercial pool installations that require ASME-certified heater construction\u003c\/li\u003e\n    \u003cli\u003eApplications where ASME is required by code but standard (non-HD) heat exchanger materials are acceptable\u003c\/li\u003e\n    \u003cli\u003eIndoor and outdoor commercial pool and spa heating at 400K BTU\u003c\/li\u003e\n    \u003cli\u003eAnyone who needs ASME certification without the additional cost of cupro nickel HD tubing\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2 style=\"margin-top:32px; font-size:24px;\"\u003eSpecifications\u003c\/h2\u003e\n\n  \u003ch3 style=\"font-size:17px; margin-top:20px;\"\u003eHeating Performance\u003c\/h3\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse; margin-bottom:16px; font-size:14px;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea; width:40%;\"\u003e\u003cstrong\u003eBTU Input \/ Output\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e400,000 BTU\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eFuel Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eNatural Gas\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eIgnition\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eDigital IID (Intermittent Ignition Device)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eEmissions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eLow NOx\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eMax Flow Rate\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e120 GPM\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3 style=\"font-size:17px; margin-top:20px;\"\u003eConstruction\u003c\/h3\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse; margin-bottom:16px; font-size:14px;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea; width:40%;\"\u003e\u003cstrong\u003eControl Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eDigital (Indicator Lights)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3 style=\"font-size:17px; margin-top:20px;\"\u003eInstallation\u003c\/h3\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse; margin-bottom:16px; font-size:14px;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea; width:40%;\"\u003e\u003cstrong\u003eGas Connection\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e0.75 in\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e120V \/ 240V\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eFrequency\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e60 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003ePhase\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eSingle\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eApplication\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eIndoor \/ Outdoor \/ Pool \/ Spa\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3 style=\"font-size:17px; margin-top:20px;\"\u003ePhysical\u003c\/h3\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse; margin-bottom:16px; font-size:14px;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea; width:40%;\"\u003e\u003cstrong\u003eProduct Weight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e149 lb\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eCabinet Dimensions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e23 W × 28.2 D × 21 H in\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eShipping Dimensions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e36 × 24 × 30 in\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3 style=\"font-size:17px; margin-top:20px;\"\u003eApprovals \u0026amp; Warranty\u003c\/h3\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse; margin-bottom:16px; font-size:14px;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea; width:40%;\"\u003e\u003cstrong\u003eCertifications\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eASME Certified\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eEnergy Efficient\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eYes (Green Certified)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\u003e\u003cstrong\u003eWarranty\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e2 Years\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch2 style=\"margin-top:32px; font-size:24px;\"\u003eWhat's in the Box\u003c\/h2\u003e\n  \u003cul style=\"font-size:15px; line-height:1.7;\"\u003e\n    \u003cli\u003ePentair MasterTemp Digital IID ASME 400K Natural Gas Heater\u003c\/li\u003e\n    \u003cli\u003eUnion Fittings\u003c\/li\u003e\n    \u003cli\u003eUser Manual\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2 style=\"margin-top:32px; font-size:24px;\"\u003eWarranty\u003c\/h2\u003e\n  \u003cp\u003eThe MasterTemp Digital IID ASME 400K comes with a 2-year manufacturer warranty from Pentair. Clearflow Pool Supply is an authorized Pentair dealer and will assist with any warranty service needed.\u003c\/p\u003e\n\n  \u003ch2 style=\"margin-top:32px; font-size:24px;\"\u003eDownloads\u003c\/h2\u003e\n  \u003cul style=\"font-size:15px; line-height:1.7;\"\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/poolimages.azureedge.net\/insite\/Product\/Documents\/PU\/R-\/15\/PUR-15-0775-2-bro.pdf\"\u003eProduct Brochure (PDF)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/poolimages.azureedge.net\/insite\/Product\/Documents\/PU\/R-\/15\/PUR-15-0775-1-ops.pdf\"\u003eOperating Manual (PDF)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/poolimages.azureedge.net\/insite\/Product\/Documents\/PU\/R-\/15\/PUR-15-0775-tech.pdf\"\u003eTechnical Manual (PDF)\u003c\/a\u003e\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2 style=\"margin-top:32px; font-size:24px;\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\n  \u003cdetails style=\"padding:14px 0;\"\u003e\n    \u003csummary style=\"font-weight:600; cursor:pointer; font-size:15px; border:none;\"\u003eWhat is the difference between this (460775) and the 461021 HD ASME model?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eBoth are ASME-certified 400K BTU MasterTemp natural gas heaters with Digital IID ignition. The 461021 adds heavy-duty cupro nickel tubing specifically rated for low pH, high flow, and heavy use applications. The 460775 uses standard heat exchanger materials — appropriate when ASME certification is required by code but HD tubing isn't necessary for the water chemistry or application.\u003c\/p\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"padding:14px 0;\"\u003e\n    \u003csummary style=\"font-weight:600; cursor:pointer; font-size:15px; border:none;\"\u003eWhat does ASME certified mean for this heater?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eASME (American Society of Mechanical Engineers) certification means the heat exchanger was built to the most rigorous pressure vessel standards. Many commercial pool installations — hotels, fitness centers, aquatic facilities — require ASME-certified heaters per local code.\u003c\/p\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"padding:14px 0;\"\u003e\n    \u003csummary style=\"font-weight:600; cursor:pointer; font-size:15px; border:none;\"\u003eDoes this heater require professional installation?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eYes. Gas heater installation involves connecting to a natural gas supply line, electrical wiring, and proper venting. A licensed contractor must perform the installation to ensure safety, local code compliance, and warranty validity.\u003c\/p\u003e\n  \u003c\/details\u003e\n\n  \u003cdetails style=\"padding:14px 0;\"\u003e\n    \u003csummary style=\"font-weight:600; cursor:pointer; font-size:15px; border:none;\"\u003eCan it be used indoors?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eYes. The MasterTemp is rated for both indoor and outdoor installation. Indoor installations require proper venting per local code. Consult the operating manual and a licensed contractor for indoor venting requirements.\u003c\/p\u003e\n  \u003c\/details\u003e\n\n\u003c\/div\u003e","brand":"Pentair","offers":[{"title":"Default Title","offer_id":48954876395771,"sku":"460775","price":5749.56,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0807\/4418\/6107\/files\/461020__62497_82cc818a-1f69-4bbb-946c-31f92eb951ae.jpg?v=1780895094","url":"https:\/\/clearflowpoolsupply.com\/products\/pentair-mastertemp-digital-iid-asme-natural-gas-low-nox-heater-400k-btu","provider":"ClearFlow Pool Supply","version":"1.0","type":"link"}