Pentair Max-E-Therm® 400 HD Natural Gas Pool & Spa Heater 400K BTU

The Pentair Max-E-Therm® 400HD is a heavy-duty, 400,000 BTU natural gas heater engineered for rapid heating and extreme resilience in high-demand pool and spa environments. This "HD" model is specifically upgraded with a high-performance cupro-nickel heat exchanger, providing a robust defense against the corrosive effects of salt-chlorination systems and fluctuating water chemistry. It utilizes an advanced pre-mixed combustion system that optimizes the air-to-gas ratio, ensuring industry-leading heat-up times and high energy efficiency while maintaining an eco-friendly "Low NOx" certification. The unit is housed in a sleek, matte-black enclosure made of Dura-Glas™—a high-density, rust-proof composite resin designed to survive the harshest outdoor elements and chemical exposure without corroding or fading. Featuring an intuitive digital control panel with self-diagnostic alerts and precise temperature management, the Max-E-Therm 400HD offers a sophisticated user experience alongside its industrial power. Despite its compact, space-saving footprint, the reinforced internal firebox and substantial cupro-nickel components provide a solid, professional-grade construction. The Pentair Max-E-Therm 400HD Natural Gas Heater weighs approximately 138 pounds, serving as a durable, long-lasting, and powerful heating solution for large residential and commercial aquatic systems.