viessmann 100w 200w

Hello , struggeling with hot water - I’ve cleared the plate to plate and all pipes and flushed all the crap out. But still the temperature climbs too high and the waters like warm ? help please

Hi, Looking at the viessmann system boilers available, the Viessmann Vitodens 100-W System Boiler 30 but for just under £200 more I could have the 200-W version. Its hard to make out what the main differences are though, weather compensation sounds useful but this is just a replacement boiler...