The boiler thermostat is controlled by the big orange control knob which you cant miss once you remove the boiler case's lower door panel.
To get to the thermostat itself you need to remove & open the black control box which contains it (release screw on front, ease box backwards and then downwards to free it. You'll also need to disconnect the electrode lead from electrode (just beneath inspection hole), disconnect the 9 pin plug and remove the phials from the thermostat pocket on the front of the boiler.
Nige, November 2007
