Reliance Non-Condensing Propane Gas Tankless Water Heater, Indoor Installations Only, 1 Major Appliance Or Shower At A Time, No Standing Pilot, 1/2 Gallon Minimum Water Flow Ignites Burner, Maximum 140,000 BTU Input, Delivers 5.1 Gallons Per Minute At 45 Degree Fahrenheit Rise, Vertical or Horizontal Venting Allowed, Requires 4" Category III Stainless Steel Vent Pipe & Fittings, All Venting Material Purchased Separately, 2 Optional Horizontal Vent Kits Depending On Wall Thickness At Vent Penetration, TV #148-892, 5" To 10" Outside Wall Thickness, TV #148-891, 12" to 18" Outside Wall Thickness, Built-In Freeze Protection, 120Vac 60Hz Electrical, Modulating Gas Valve, 3/4" Gas & Water Connections, Propane Gas Only, Water Pressure 15 Minimum PSI to 150 Maximum PSI, Optional Kit that Includes 2 Isolation Service Valves &1 Required Pressure Only Valve Sold Separately, .82 Energy Factor, Energy Star Qualified, Warranty 15 Years on Heat Exchanger, 5 Years On Parts.