Help please! I have a Ariston Microcombi 23 mffi boiler, installed approx 3yrs ago, the central heating has never been a problem feeding 7 rads but can never get much tempature in the DHW side, it also goes from warm to cold to warm etc when running the tap. Have just had it serviced this week, a new flow switch fitted & flow valves adjusted but the problem is still there. Is it that the boiler is just not up to it? Is there a replacement boiler out there that could guarantee me a nice hot bath or would even provide water hot enough so the Mrs can wash the dishes without having to boil the kettle.