Copied from a heating section posting!
I've upgraded my gas boiler to a Vokera mynute 25 A. Now the plumber could not wire the boiler so I called a spark and when he wired the boiler he blew the PCB. After I called a gas service guy he said that boiler was a low voltage contact and that he needed to wire the switch live from the external controls to a 230v ac- dc relay board and then back to the PCB.