Ariston Micro Combi hot water problem

[dickvandyke]

Hi,

I'm looking for a pointer as to what might be the problem with my Ariston micro combi boiler.

A few days ago it wouldn't power on. So I got an engineer to come and look at it, he replaced the PCB and everything fired up again.

The central heating now appears to be fine and the radiators are all hot. The issue I'm having is that the hot water from the taps isn't the same temperature level I was getting before. Now when the tap is first turned on I get very hot water shortly followed by a fall in temperature and from then on it is just lukewarm.

I guess I'll have to get the engineer back but I'd like to get an idea of what could be causing this.

Thanks,
Steve