Burner. To adapt it to different gases, it is sufficient to exchange the injectors. (Withstainless steel heads specially designed for the combustion of butane/propane andnatural gases)Piezoelectric front igniterTemperature and power selector switchSpecial hydraulic arrangement. It automatically activates the water heatingmechanisms whenever a hot water tap is opened. It is also SAFE, since it opens thepassage of gas to the burner only when water flows through the heat exchanger.Built-in flue draught extractor. It ensures a correct combustion, whatever thevariation of the draught in the exhaust duct (chimney). A safety device stops the unitin the event of abnormal flue evacuation.Ignition safety valve. Thermo-electric system, which allows the gas to flow in theburner only when the pilot flame is ignited.Automatic water flow regulatorFlexible hot water connectionC Hot water outlet: R 1/2”.F Cold water inlet: R 1/2”.G1 Butane/propane inlet: Ø 12 mm ext.G2 Natural gas inlet: Ø 12 mm ext.* Ø Interior ØNominal consumption Nominal 20,7 kW Useful power Nominal 17.4 kwWater flow  40°C (ΔT = 25°C)  10 l/minand temperature 65°C (ΔT = 50°C)  5  l/minMaximum water pressure 10 barDimensions LxHxP   360x660x206 mm