The Vaillant ecoCOMPACT VSC 256/4-5 100 is a 25 kW indoor condensing boiler, convertible to natural gas, with an integrated 90 L water heater. It covers homes up to approximately 500 m², is class A for heating and DHW, and produces up to 24.4 l/min of hot water. The ELGA system automatically adjusts the air-gas ratio to reduce consumption. The compact design, which can be separated into two parts with a door that opens on both sides, facilitates installation and maintenance. High-efficiency pumps and multi-zone management make it suitable even for complex systems.