ENERGY STAR® Qualified Featuring SRT™ Scale Reduction Technology STEADISET® Technology Built-In Recirculation Pump Built-in Digital Control Active Bypass Modulation-Segmented burner with 22:1 turn down ratio Self-Calibrating Fan and Gas Valve Optional external Pump control kit Venting Flexibility Gas Connection Flexibility - 1/2", 3/4", or 1" Top Water Connections Inlet Water Filter-External access for easy maintenance Space Saving Installation Built-in Freeze Protection Easy LP Gas Field Convertibility-Purchase of additional kit NOT required to convert from NG to LP Pressure Relief Valve Included (Integral port) Built-in Flush Ports Flushing Condensate Trap Complies with the Latest Ultra-Low NOx Requirement (10 ng/J NOx limit)