how can i fix my vokera maxim combi boiler?

my combi is about 12 years old, but lately it has been cutting out when the central heating and sometimes the water only is on ,it goes back on if i press the orange button but sometimes i have to switch it off and on again, i was wondering if it is just the orange micro switch or maybe the diverter valve that was faulty it was just replaced in november is it something i can do myself

natreay
April 2010