Got a combi boiler and having trouble with hot water to taps.If tap is open halfway i get constant hot water,if tap is fully open boiler starts and stops giving intermittent hot and cold water.Was thinking divertor between the two heat exchangers,flow switch or could air in pump be problem ? Should add central heating side is 100%

Not a heating Engimineer mate but I had this problem with an old Vokera boiler I had. It turned out to be the inlet water pressure sensor... the plunger in the valve kept sticking causing the problems you describe. As the boiler was so unreliable anyway I decided to bin it and get a better more reliable one. I now have a Worcestershire/Bosch which is awesome in comparison.

Steve

Thanks bud i will check it out