{"product_id":"pentair-max-e-therm-333-hd-natural-gas-pool-spa-heater-333k-btu","title":"Pentair Max-E-Therm® 333 HD 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 HD Natural Gas Pool \u0026amp; Spa Heater 333K BTU\u003c\/strong\u003e brings proven Max-E-Therm performance with heavy-duty cupro nickel tubing — built for demanding applications including low pH, high flow, and heavy use. Save money and energy with 84% thermal efficiency, the highest in its class.\u003c\/p\u003e\n\n  \u003cp\u003eBuilt by Pentair (Sta-Rite) with a Dura-Glas® rustproof matte black enclosure, compact retrofit design, Low NOx certification, optional energy-saving automatic bypass, and direct Sta-Rite System:3 Mod Media filter compatibility. 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 (HD)\u003c\/h3\u003e\n      \u003cp style=\"margin:0; font-size:14px; line-height:1.5;\"\u003eBest-in-class efficiency with heavy-duty cupro nickel tubing for demanding applications — the unique 333K BTU size in the Max-E-Therm HD lineup.\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 — superior corrosion resistance.\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;\"\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 HD cupro nickel durability\u003c\/li\u003e\n    \u003cli\u003eSalt water pools, low pH applications, and high-flow installations requiring cupro nickel tubing\u003c\/li\u003e\n    \u003cli\u003eRetrofit installations where the compact Max-E-Therm footprint is essential\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\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\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 HD 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 HD 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-15-509-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-15-509-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-15-509-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;\"\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 HD lineup includes 200K, 333K, and 400K BTU sizes. The 333K sits between the 200K and 400K — suited for pools in the 20,000–35,000 gallon range where 200K BTU is insufficient but 400K BTU is more than needed. It's particularly useful when a precise BTU calculation lands in that middle zone.\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 HD 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  \u003cdetails style=\"padding:14px 0;\"\u003e\n    \u003csummary style=\"font-weight:600; cursor:pointer; font-size:15px; border:none;\"\u003eIs it compatible with salt water pools?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eYes. The cupro nickel tubing in the HD model provides superior resistance to salt water corrosion — the recommended choice for salt water pool installations in the Max-E-Therm lineup.\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 the automatic bypass option?\u003c\/summary\u003e\n    \u003cp style=\"margin-top:10px; font-size:14px; line-height:1.6;\"\u003eThe optional automatic bypass diverts flow around the heater when it's not actively heating, reducing hydraulic resistance and lowering pump energy consumption — an energy-saving add-on for efficiency-focused installations.\u003c\/p\u003e\n  \u003c\/details\u003e\n\n\u003c\/div\u003e","brand":"Pentair","offers":[{"title":"Default Title","offer_id":48954880393467,"sku":"SR333HD","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_7ef94564-3460-493a-8eb0-5f09d6cac443.jpg?v=1780895631","url":"https:\/\/clearflowpoolsupply.com\/products\/pentair-max-e-therm-333-hd-natural-gas-pool-spa-heater-333k-btu","provider":"ClearFlow Pool Supply","version":"1.0","type":"link"}