Rafal Kaczynski
Hello Ulrike DHW flow do not depent of heating output of Combi Boiler;) it depend of mains water pressure;) To have a very good flow of hot water Unvented Hot Water Cylinder is a option as it work under main water pressure so water flow is a much higher than from combi. It is true that combi boiler with higher heat output will warm water quicker than with lower but it all depend how efficient heat exchanger is ( how quick warm water) I hope this can help regards Raf
