{"product_id":"pentair-max-e-therm-333-natural-gas-pool-spa-heater-333k-btu","title":"Pentair Max-E-Therm® 333 Natural Gas Pool \u0026 Spa Heater 333K 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 Max-E-Therm® 333 Natural Gas Pool \u0026amp; Spa Heater 333K BTU\u003c\/strong\u003e lets you save money and energy without compromise. Already known for dependability and efficiency, the Max-E-Therm now offers smart features and an optional energy-saving automatic bypass to help ensure your pool is ready whenever you are.\u003c\/p\u003e\n\n  \u003cp\u003eBuilt by Pentair (Sta-Rite) with an 84% efficiency rating — rated first in its class — the Max-E-Therm 333 features a lightweight, compact Dura-Glas® rustproof matte black enclosure, Low NOx certification, and direct compatibility with Sta-Rite System:3 Mod Media filters. CSA certified for indoor and outdoor use. 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;\"\u003e333,000 BTU — 84% Efficiency\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eRated first in its class for highest energy efficiency at the 333K BTU level.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eLightest Heater in Its Class\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eLightweight design makes installation easier and reduces labor costs.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eCompact Retrofit Design\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eIdeal for retrofit installations where space is limited on an existing equipment pad.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eOptional Automatic Bypass\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eEnergy-saving automatic bypass option to optimize operating costs.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eEasy Gas Source Switching\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eConvert between natural gas and propane with installation of a separate orifice.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eDura-Glas® Rustproof Housing\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eSleek matte black enclosure resists rust and corrosion for long service life.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eLow NOx — Environmentally Friendly\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eAll units are Low NOx certified.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eSta-Rite System:3 Compatible\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eDirect-connects to Sta-Rite System:3 Mod Media filter or fits other systems easily.\u003c\/p\u003e\n    \u003c\/div\u003e\n    \u003cdiv\u003e\n      \u003ch3 style=\"font-size:16px; margin-bottom:6px;\"\u003eIndoor and Outdoor Certified\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eCSA certified 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 residential 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\u003ePool and spa owners whose heat load falls between 200K and 400K BTU wanting Max-E-Therm efficiency\u003c\/li\u003e\n    \u003cli\u003eRetrofit installations where the compact Max-E-Therm footprint is essential\u003c\/li\u003e\n    \u003cli\u003eSta-Rite System:3 filter owners who want direct heater integration\u003c\/li\u003e\n    \u003cli\u003eAnyone who may want to switch between natural gas and propane in the future\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\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e333,000 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\u003eThermal Efficiency\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e84%\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 (convertible to LP)\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\u003eFlow Rate\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003e33–120 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\u003eEnclosure\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"padding:10px 12px; border:1px solid #eaeaea;\"\u003eDura-Glas® (Rustproof, Matte Black)\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\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\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;\"\u003e138 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;\"\u003e25.15 W × 30 D × 26 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;\"\u003e27.75 × 34.25 × 32 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;\"\u003eCSA 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 Max-E-Therm 333 Natural Gas Pool \u0026amp; Spa 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 Max-E-Therm 333 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\/ST\/A-\/15\/STA-15-502-bro.pdf\"\u003eProduct Brochure (PDF)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/poolimages.azureedge.net\/insite\/Product\/Documents\/ST\/A-\/15\/STA-15-502-ig.pdf\"\u003eInstall Guide (PDF)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/poolimages.azureedge.net\/insite\/Product\/Documents\/ST\/A-\/15\/STA-15-502-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 the Max-E-Therm 333 (SR333NA) and the 333 HD (SR333HD)?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eThe Max-E-Therm 333 HD adds cupro nickel tubing to the standard 333 platform. Cupro nickel provides significantly better corrosion resistance for low pH, high flow, salt water, and heavy use applications. If your pool has aggressive water chemistry or high bather loads, the HD is the right choice. Both share the same 84% efficiency, Dura-Glas housing, and compact retrofit footprint.\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;\"\u003eWhy 333K BTU — where does this fit in the lineup?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eThe Max-E-Therm standard lineup includes 200K, 333K, and 400K BTU sizes. The 333K sits between 200K and 400K — suited for pools in the 20,000–35,000 gallon range when a precise BTU calculation lands in that middle zone. It's a common choice for mid-size residential in-ground pools.\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 I convert this to liquid propane?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eYes. The Max-E-Therm 333 can be converted from natural gas to liquid propane by installing a separate LP orifice kit (sold separately).\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 pool contractor or plumber 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":48954892255483,"sku":"SR333NA","price":5452.48,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0807\/4418\/6107\/files\/14821-available-in-store-only-tradegrade-sta-rite-sr400hd-max-e-therm-hd-low-nox-cu-ni-heater---natural-gas---400k-btu-__94775_3789bb11-bcd8-48ad-995e-d2fa9983b2d4.jpg?v=1780896235","url":"https:\/\/clearflowpoolsupply.com\/products\/pentair-max-e-therm-333-natural-gas-pool-spa-heater-333k-btu","provider":"ClearFlow Pool Supply","version":"1.0","type":"link"}