Have just had a combi boiler system fitted in an old cottage that is being renovated, thought it was the best system because I did not need a water tank and space was scarce however I,ve been told that power showers cannot run off combis and that to get hot water you have to turn the whole system on as they do not have an immersion heater type option - am very confused and regretting not sticking with the old system- can anyone give me advice on best way to use combi and what shower to buy- thanks again