Built by Pentair, this MasterTemp HD ASME Pool Heater is a trusted pick for pool owners and service pros alike.

The Pentair MasterTemp HD ASME Pool Heater 461021 delivers 400,000 BTU of powerful, trustworthy heating with built-in ASME certification for high-performance applications. Designed to meet rigorous commercial and residential standards, this natural gas heater blends robust construction, efficient heat transfer, and advanced control features to extend your swimming season with consistent warmth.

Featuring a high‑efficiency heat exchanger, electronic ignition, and intuitive digital controls, the MasterTemp HD ASME model provides fast warm‑up times, optimized fuel use, and dependable operation even under demanding conditions. Its ASME‑rated design ensures enhanced safety and durability, making it ideal for larger pools, heavy use, or installations requiring certified compliance.

Trusted by pool professionals — order the Pentair MasterTemp HD ASME Pool Heater today and ship it fast.