{"product_id":"pentair-sr400na-sta-rite-max-e-therm-400k-btu-heater-natural-gas-pool-spa-heating","title":"Pentair SR400NA Sta-Rite Max-E-Therm 400K BTU Heater – Natural Gas Pool \u0026 Spa Heating","description":"\u003cp data-start=\"600\" data-end=\"954\"\u003eThe \u003cstrong data-start=\"604\" data-end=\"704\"\u003e\u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003ePentair\u003c\/span\u003e\u003c\/span\u003e Sta-Rite Max-E-Therm SR400NA Natural Gas Pool \u0026amp; Spa Heater\u003c\/strong\u003e delivers \u003cstrong data-start=\"714\" data-end=\"758\"\u003epowerful 400,000 BTU heating performance\u003c\/strong\u003e in a compact, energy-efficient design. Built for fast heat-up times and reliable operation, Max-E-Therm heaters are trusted for both residential and light commercial pool and spa installations.\u003c\/p\u003e \u003cp data-start=\"956\" data-end=\"1337\"\u003eFeaturing a \u003cstrong data-start=\"968\" data-end=\"1009\"\u003ehigh-efficiency copper heat exchanger\u003c\/strong\u003e, advanced digital controls, and a corrosion-resistant composite cabinet, the SR400NA provides consistent temperature control while operating quietly and efficiently. Its space-saving footprint and straightforward installation make it an excellent choice for equipment pads with limited room—without sacrificing heating power.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSupplied under part number SR400NA for exact-match ordering.\u003c\/li\u003e\n\u003cli\u003eBTU rating: 400K BTU.\u003c\/li\u003e\n\u003cli\u003eSized by BTU output — match the rating and fuel type to your existing unit.\u003c\/li\u003e\n\u003cli\u003eShips from our US warehouse with tracking on dispatch.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Pentair\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer part number:\u003c\/strong\u003e SR400NA\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Pool Heaters\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e New\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBTU rating:\u003c\/strong\u003e 400K BTU\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC \/ GTIN:\u003c\/strong\u003e 022315208285\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShipping weight:\u003c\/strong\u003e 140 lb\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003ch3\u003eWhat part number is this pool heater?\u003c\/h3\u003e\u003cp\u003eThis item is supplied under part number SR400NA. Match that number against your equipment's parts diagram before ordering.\u003c\/p\u003e\u003ch3\u003eDoes the BTU rating have to match my old heater?\u003c\/h3\u003e\u003cp\u003eThe BTU rating should match or exceed your previous heater. Undersizing means the pool never reaches temperature on cold days; oversizing costs more up front but heats faster and cycles less.\u003c\/p\u003e\u003ch3\u003eCan this run on propane instead of natural gas?\u003c\/h3\u003e\u003cp\u003eNo. Gas pool heaters are built for one fuel and require a manufacturer conversion kit to change. Check the data plate on your existing unit and order the matching fuel type.\u003c\/p\u003e\u003ch3\u003eWhat size heater do I need for my pool?\u003c\/h3\u003e\u003cp\u003eA common rule is 1 BTU per gallon as a minimum, increased for windy sites, uncovered pools, or cold climates. A 20,000 gallon pool typically starts at 250,000 BTU.\u003c\/p\u003e\u003ch3\u003eDo I need a professional to install a pool heater?\u003c\/h3\u003e\u003cp\u003eGas heaters involve gas line sizing, venting and electrical connections, and most jurisdictions require a licensed installer plus a permit. Improper installation voids the manufacturer warranty.\u003c\/p\u003e\u003ch3\u003eHow do I confirm this part fits my equipment?\u003c\/h3\u003e\u003cp\u003eCheck the part number stamped on the component you are replacing, or find it on the parts schematic in your owner's manual. If the number differs or is unreadable, send us your equipment model and serial number and we will verify fitment before you order.\u003c\/p\u003e\u003ch3\u003eHow quickly does this ship?\u003c\/h3\u003e\u003cp\u003eIn-stock items ship from our US warehouse on business days. You will receive tracking by email once the order leaves the warehouse.\u003c\/p\u003e\u003ch3\u003eCan I return it if I ordered the wrong part?\u003c\/h3\u003e\u003cp\u003eUnopened, uninstalled items can be returned within 30 days. Equipment that has been installed or plumbed cannot be returned, so confirm fitment before installation.\u003c\/p\u003e\u003ch3\u003eIs this covered by a warranty?\u003c\/h3\u003e\u003cp\u003eManufacturer warranty terms vary by brand and product. Warranty claims generally require proof of purchase and, on installed equipment, evidence of professional installation.\u003c\/p\u003e\u003cscript type=\"application\/ld+json\"\u003e{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"What part number is this pool heater?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"This item is supplied under part number SR400NA. 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