L-line heat exchangers are copper- or nickel-brazed plate heat exchangers intended for standard liquid-liquid heating or cooling systems. The optimal shape of the flow channels provides a compromise between achieving low-flow resistance and high-heat exchange efficiency. The tightness of the structure and the permanent assembly of the plates ensures the soldering process in a vacuum furnace. A proven solution in household heating systems, heat distribution centres, boilers, water-jacketed stoves. For each exchanger size, it is possible to choose different connection sizes and a two-flow version of the exchanger with a high heat exchange efficiency while operating in more demanding parameters.