ProLine® Direct Vent Design. One-pipe, dual-channel draws all make-up air from outside the home, eliminating problems caused by insufficient indoor ventilation. All units are FVIR compliant. Horizontal air intake and venting on all models up to 80 inches from outside the wall with no electrical power needed. 6-year limited Tank warranty, 6-year parts warranty for Residential applications Intelligent Control Logic - The internal microprocessor provides enhanced operating parameters and tighter differentials for precise sensing and faster heating response to optimize performance Diffuser Dip Tube - Helps reduce lime and sediment buildup, maximizes hot water output. - Made from long-lasting PEX cross-linked polymer. Self-Powered Electronic Gas Valve - Uses a thermopile to generate the power needed to operate the electronic gas control without requiring an external power source CoreGard™ Anode Rod - Our anode rods have a stainless steel core that extends the life of the anode rod allowing superior tank protection far longer than standard anode rods Diagnostics - The electronic gas control incorporates an LED status indicator that monitors system operation and service diagnostics Push Button Piezo Ignitor - Makes lighting the pilot fast and easy with one hand push button spark ignition Durable, Tamper-Resistant Brass Drain Valve Heat Trap Nipples - Factory-installed Fused Ceramic Tank Shield - Provides superior corrosion resistance compared to the industry-standards glass lining CSA Certified and ASME Rated T&P Relief Valve Code Compliance - UBC, CEC, SBCC, HUD and BOCA National Codes. Meets the thermal efficiency and standby loss requirements of the U.S. Department of Energy and current edition of ASHRAE/IESNA 90.1 and meets the Federal Energy Efficiency Standards effective January 20 2004, according to the National Appliance Energy Conservation Act (NAECA) of 1992.