How can I fix my Baxi Combi Boiler hot water?

I had exactly the same problem on my Baxi Genesis 80. Eventually the problem got worse and the hot water would run for a few seconds and then go cold but at first it cycles just as you describe. It turns out that the heat exchanger was blocked with small bits of metal that had flaked off from the inside of the radiators, and changing it solved the problem! Hope this helps!

Paul Cooper
December 2005