"my 16 yr old Biasi broke so decided to change it for a new model. After researching the technical data on this combi I decided to buy it as it was an almost direct replacement for the old 424s. Apart from the gas pipe everything lined up including the flue which had to be moved down and over slightly. The only quib was the expansion tank was off centre so I had to realight it but in doing so loosened off the pipe which then leaked when I had fitted the boiler, so it had to all come off again. Not pleased but once installed its a good combi for £550!"