{"product_id":"pentair-mastertemp-digital-iid-hd-natural-gas-low-nox-heater-400k-asme","title":"Pentair MasterTemp® Digital IID Heavy Duty Natural Gas Low NOx Heater 400K ASME HD 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 Heavy Duty Natural Gas Low NOx Heater 400K ASME HD BTU\u003c\/strong\u003e delivers all the efficiency, convenience, and reliability of the MasterTemp platform — plus commercial-grade ASME certification and heavy-duty cupro-nickel tubing rated for the most demanding pool environments. User-friendly indicator lights make system operation and monitoring a snap, while the compact design and super-quiet operation won't intrude on poolside leisure.\u003c\/p\u003e\n\n  \u003cp\u003eBuilt by Pentair with ASME-certified construction, cupro-nickel tubing, 400,000 BTU natural gas output, and a Digital IID ignition system — this is the HD MasterTemp for commercial applications where standard residential certification isn't sufficient. 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 installations.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003e400,000 BTU Heavy-Duty Output\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eMaximum-capacity natural gas 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;\"\u003eCupro-Nickel Tubing (HD)\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eWithstands low pH, high flow, and heavy use — the most demanding pool applications.\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 with low pH, high flow, or heavy bather loads demanding HD cupro-nickel tubing\u003c\/li\u003e\n    \u003cli\u003eIndoor and outdoor commercial pool and spa heating at 400K BTU\u003c\/li\u003e\n    \u003cli\u003eAnyone who needs the MasterTemp platform with ASME certification\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\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\u003eTubing Material\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eCupro Nickel (HD)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:10px 12px; background:#fafafa; border:1px solid #eaeaea;\"\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 × 25 × 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\u003eEmissions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eLow NOx (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 HD 400K ASME 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 HD 400K ASME 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-15-0779-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-15-0779-1-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-15-0779-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 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 designed and built to meet the most rigorous pressure vessel standards in the industry. Many commercial pool installations — hotels, fitness centers, aquatic facilities — require ASME-certified heaters per local code. The standard residential MasterTemp models are not ASME certified.\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 is a Digital IID ignition system?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eIID stands for Intermittent Ignition Device — an electronic ignition system that only sparks when the heater needs to fire, rather than maintaining a continuous standing pilot light. This improves energy efficiency and reliability compared to standing pilot designs.\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;\"\u003eHow does this differ from the standard 400K HD MasterTemp (460805)?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eThe 461021 adds ASME certification to the HD platform — the key distinction is that ASME certification is required for many commercial pool codes. Both share the same cupro-nickel tubing, 400K BTU output, and compact 23-inch cabinet. Choose 461021 when ASME certification is required by code or specification.\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\u003c\/div\u003e","brand":"Pentair","offers":[{"title":"Default Title","offer_id":48954827964667,"sku":"461021","price":6398.71,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0807\/4418\/6107\/files\/461020__62497.jpg?v=1780893181","url":"https:\/\/clearflowpoolsupply.com\/products\/pentair-mastertemp-digital-iid-hd-natural-gas-low-nox-heater-400k-asme","provider":"ClearFlow Pool Supply","version":"1.0","type":"link"}