Sta-Rite Max-E-Therm 400k BTU Natural Gas Heater | SR400NA

Product Overview The Sta-Rite Max-E-Therm® 400 Natural Gas Pool and Spa Heater delivers powerful, fast heating in a compact and corrosion-resistant design. With a 400,000 BTU input, the SR400NA is designed to quickly raise pool or spa temperatures while providing reliable and energy-efficient operation. Its digital controls, self-diagnostic system, low-NOx burner, and rustproof Dura-Glas® exterior make it an excellent choice for residential in-ground pools and spas. The compact footprint also makes the Max-E-Therm ideal for new equipment pads and replacement installations where space is limited. Key Features 400,000 BTU natural gas heating capacity 84% thermal efficiency Fast pool and spa heating Digital temperature control panel Dual pool and spa thermostat settings Self-diagnostic operating controls Low-NOx certified burner system Rustproof Dura-Glas® exterior housing Compact equipment-pad footprint Built-in plumbing unions 120V or 240V electrical operation Compatible with supported pool automation systems Suitable for indoor or outdoor installation when properly configured Benefits Quickly heats large residential pools and spas Compact design saves equipment-pad space Digital controls provide simple temperature management Corrosion-resistant housing withstands outdoor conditions Low-NOx operation meets applicable air-quality requirements Dual-voltage design provides installation flexibility Natural gas operation delivers dependable heating performance Specifications Specification Details Brand Sta-Rite by Pentair Product Series Max-E-Therm® Model SR400NA Manufacturer Part Number SR400NA SKU SR400NA Barcode / UPC 022315208285 Product Type Pool and Spa Gas Heater Heating Capacity 400,000 BTU Fuel Type Natural Gas Thermal Efficiency 84% Heat Exchanger Copper Voltage 120V / 240V Frequency 60 Hz Electrical Phase Single Phase Plumbing Connection 2" Minimum Water Flow 40 GPM Maximum Water Flow 120 GPM Control Type Digital Pool and Spa Thermostats Yes Self-Diagnostics Yes Emissions Rating Low NOx Automation Compatible Yes Exterior Housing Rustproof Dura-Glas® Installation Location Indoor or Outdoor When Properly Configured Application Residential In-Ground Pools and Spas Condition New What’s Included Sta-Rite Max-E-Therm SR400NA heater Factory-installed digital controls Factory-installed copper heat exchanger Inlet and outlet plumbing unions Installation and operation documentation Gas piping, electrical wiring, venting components, plumbing materials, automation accessories, and installation labor are not included unless specifically stated. Installation Information Professional installation is required. Before ordering, confirm the natural gas supply, gas-line capacity, inlet gas pressure, electrical service, plumbing size, ventilation requirements, equipment-pad clearance, and heater sizing. Model SR400NA contains a standard copper heat exchanger. For saltwater pools, high-flow applications, or chemically demanding installations, confirm whether a cupro-nickel or other upgraded model is more appropriate. Warranty Information This heater is covered by Pentair’s limited manufacturer warranty when purchased, installed, registered, and operated according to current warranty requirements. Proof of purchase, product registration, and proof of professional installation may be required. Damage caused by improper installation, incorrect gas pressure, restricted water flow, freezing, poor water chemistry, corrosion, misuse, or unauthorized modifications is not covered. Pentair TradeGrade products sold online may receive reduced warranty coverage unless the purchase and installation meet Pentair’s authorized TradeGrade requirements. Freight Delivery Notice This product ships by freight. Inspect the heater and packaging before signing the delivery receipt. Any visible damage must be documented on the carrier’s paperwork and photographed immediately. Do not sign for a visibly damaged shipment as being received in good condition. Customer Questions What fuel does the SR400NA use? This model is factory-configured for natural gas. How much heating power does it provide? The heater has a 400,000 BTU input rating. Can it be used with pool automation? Yes. It can operate with supported pool automation systems when properly connected. Is this the saltwater model? No. The SR400NA uses a standard copper heat exchanger. Confirm suitability before using it on a saltwater pool. Can it be installed indoors? Yes, provided all required combustion-air and venting components are properly installed.