The problem is it's a combi, when the heating cuts in it takes the heat away and theres not enough for the hot water heat exchanger three way valve works ok flow switch ok. We get round this problem by manually switching off the heating via room stat then hot water not to bad. What hassle when you just want to run hot water in the kitchen sink. Boiler manual shows 7.5 ltrs a minute WOW If the house is up to temp then somtimes it's ok it's just pot luck
Brian
March 2011