Remove the Phillips screw remove cover left hand corner and opposite right hand corner there will be Phillips screws remove these this will remove the head and change head only will need to wire new one back in
Eco this optimax 25c is it easy adjustment for low co looked in M.I.s can't find adjustment I see u r mr ferroli I come across a lot of these in Birmingham
What's happening is boiler runs for half hour then stops flashes up code he which according to manual means PCB but everytime I have had PCB fault boiler was completely dead . I am wondering if this is more,a overheard fault any body else come across this problem