Keith Hi,
Mine has just broken down again! with F10 That's a problem with the water level pressure switch-I have just replaced mine and it still shows the fault so I guess the computer module has packed up (it packed up once before). F8 is heater relay stuck on or pressure switch stuck on in the 'on' position I suggest changing the pressure switch it is Part No:IND110332
I hope that helps, Cris.
Cris Palmer, January 2008