Water-to-Water Indirect Domestic Hot Water System

The DURATION III is a fully packaged, water-to-water indirect domestic hot water system. Engineered to complement any boiler or other hydronic water source, the DURATION III offers low cost of ownership through simplicity, high efficiency, durability and ease of installation.

  • Recovery Rates (40°F – 140°F) — 0 – 85 GPM Domestic Water Demand
  • High quality stainless steel brazed plate heat exchanger
  • Specifically engineered to complement any boiler or other hydronic water source
  • Compact footprint is less than 5.5 ft2
  • Easy integration with BAS software via integrated Modbus RS-485 protocol
  • Requires four water connections
    – Two connections for DHW inlet/outlet
    – Two connections for boiler water inlet/outlet
  • Requires one power connection
    – A single 110V electrical power supply connection
  • Pumped Versions (D3-30P/D3-30PE and D3-50P/D3-
  • 50PE) designed to operate seamlessly with the NURO®
  • Models can be placed side-by-side in a multi-unit installation


P-K Long Term Durability To ensure longevity, the DURATION III has a durable 316L stainless steel double-wall brazed-plate heat exchanger with a true air gap. All wetted parts (potable water side) are lead free and made of robust stainless steel, copper or copper alloy materials.

Technical Data

Because we are continuously evolving our products, descriptions and technical data are subject to change without notice.

Contact your local Patterson-Kelley representative for the most up-to-date information and product application support.