Patterson-Kelley continues to deliver highly-eff icient products that adapt to the needs of any commercial building. The P-K STORM and the P-K SOLIS are the latest additions to the expansive PK family. 650-6000 MBTU Up to 97% thermal eff iciency 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 AHRI Outdoor Capabilities Variable speed combustion air blower Certified at 3.5 inch Water Column minimum gas pressure Pressure drops as low as 4.7' at 40° ΔT P-K SOLIS® 1500-3000 MBTU Up to 96% Thermal Eff iciency Full Modulation Burner with 10:1 Mechanical Turndown Ultra-Low NOx Emissions 316 SS Tube and Tube Sheet with a 304 SS Heat Exchanger Shell Removable and Hinged Door Panels allow Quick Access to the Firetubes and Burner for Easy Boiler Maintenance Zero-Clearance Capable for Side-by-Side Installation or Close Boiler Room Application AHRI Compact Design Fits Through a Standard 36 " Doorway Certified Up to 97% eff iciency Certified Up to 97% eff iciency