Lochinvar – Knight XL Commercial Gas Boilers

Commercial Boilers


The KNIGHT XL boiler is today’s smartest choice in condensing boiler performance. It has environmentally-friendly features and the exclusive Smart System™ control.


The KNIGHT® XL reflects Lochinvar’s constant commitment to providing all the options you need to serve every application. It’s engineered with Lochinvar’s exclusive SMART SYSTEM™ control and an array of other innovative features, placing it far ahead of any commercial heating boiler in its class. It promises and delivers ultimate ease of installation and maintenance. With up to 94.6% thermal efficiency, low-NOx emissions and a fully modulating burner, it’s the best “green choice” for today’s environmentally focused market.

  1. Advanced Negative Regulation Technology
    KNIGHT XL safely and reliably operates with supply gas pressure as low as 4 inches water column. Negative regulation (neg/reg) technology automatically adjusts fan speed to ensure the correct volume and mix of fuel and air throughout the firing range.
  2. Two-in-One Stainless Steel Heat Exchanger
    A primary heat exchanger combined with a secondary heat exchanger captures flue gas heat and condenses to utilize available latent energy. The stainless steel, pH-tolerant design features a weld-sealed assembly with no O-rings or gaskets and does not require special glycol. ASME Section IV approved and stamped.
  3. Fully Modulating Burner
    The SMART SYSTEM control allows fully modulating combustion with 5:1 turndown. The burner can fire as low as 20% of maximum input and modulates the firing rate up to 100% as demand increases.
  4. Direct Venting Up To 100 Feet
    KNIGHT XL offers 7 venting options and tremendous flexibility for placement of units within the building, because it permits direct-vent air intake and exhaust runs up to 100 equivalent feet.
Model NumberInput MBH Min.Input MBH Max.Thermal EfficiencyOutput MBHNet AHRI Rating MBHABCDEFGas Conn.Water Conn.Air InletVent Size
Ship. Wt.