P-K STORM® Condensing Boilers

Models: ST1250, ST1500, ST1750, ST2000, ST2500, ST3000, ST3500, ST4000, ST5000, ST6000, ST8000

Patterson-Kelley continues to transform the commercial boiler industry by offering the highest quality, most efficient, condensing products available. Our newest stainless-steel condensing boiler is designed for maximized comfort during those long cold winter days, without sacrificing savings.

Built to transform the commercial boiler market, this top-of-the-line, highly efficient condensing boiler is designed to provide long-term savings in energy costs. The P-K STORM® is AHRI Certified at 97.1% thermal efficiency with 10:1 mechanical turndown capabilities.


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Standard 10:1 Mechanical Turndown

10:1 Turndown Technology Increases Efficiency and Reduces Operating Cost

Patterson-Kelley has achieved higher turndown with a unique mechanical process that allows the gas valves to control boiler performance without increasing excess air. This results in building flexibility and efficiency.

This method delivers a 10:1 turndown rate while preserving a high dewpoint, which helps maintain high condensation levels. This higher turndown capability will provide designers the ability to match input to building loads without sacrificing efficiency and reliability. No more nuisance flame failures that have traditionally plagued high turndown boilers.

Simplified Serviceability

The heat exchanger is designed to provide simplified and quick annual maintenance. The heat exchanger door swivels open providing full access to the tubes and burner inside the unit. This makes any maintenance, including cleaning, a quick and cost-effective process.

Outdoor Technology Options Available On Models ST1250-ST2000

Factory assembled and tested for outdoor installations with efficiencies up to 97% and a 10:1 mechanical turndown rate, outdoor models come assembled from the factory without requiring time in the field to make conversions. For buildings with limited indoor space, this option on the P-K STORM® is ready for any predicted forecast.

NURO® Touch-Screen Control System

Turndown energy usage

All of our boilers are equipped with the most intuitive interface in the industry, the NURO® Touch-Screen Control. Designed to maximize efficiency, the NURO® Control System monitors and modulates the combustion and ignition of the boiler to maintain the desired outlet temperature.


  • 650-6000 MBTU
  • Up to 97% thermal efficiency
  • 316L Stainless steel coil ensures maximum corrosive resistance and durability
  • Full modulation burner with up to 10:1 mechanical turndown
  • Cabinet and heat exchanger design reduce repair and maintenance costs
  • Outdoor Capabilities
  • Variable speed combustion air blower
  • Certified at 3.5 inch Water Column minimum gas pressure
  • Low pressure drops across the unit
  • The compartmentalized design produces an efficiency of heat transfer in each section

Contact us to learn more about the Patterson-Kelley difference.

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