Pentair Max-E-Therm® 333 HD Natural Gas Pool & Spa Heater 333K BTU

The Pentair Max-E-Therm® 333HD is a heavy-duty, 333,000 BTU natural gas heater designed for rapid heating and exceptional resilience in demanding pool and spa environments. This "HD" model is specifically upgraded with a high-performance cupro-nickel heat exchanger, which provides superior protection against corrosion and erosion compared to standard copper units, making it an ideal choice for pools with salt chlorine generators or fluctuating water chemistry. It utilizes a sophisticated pre-mixed combustion system that optimizes fuel efficiency and heat-up times while maintaining an eco-friendly "Low NOx" certification. The unit is housed in a sleek, rust-proof enclosure made of Dura-Glas™—a high-density composite resin that survives harsh weather and chemical exposure better than traditional metal cabinets. Featuring an intuitive digital display with self-diagnostic alerts and dual thermostats for precise pool and spa control, the Max-E-Therm is as smart as it is powerful. Despite its relatively compact and space-saving design, the industrial-grade internal components and reinforced firebox result in a substantial, professional-grade build. The Pentair Max-E-Therm 333HD Natural Gas Heater weighs approximately 138 pounds, offering a rugged, long-lasting, and high-output heating solution for modern aquatic facilities.