I have an intermittent fault on my above boiler, although it's self diagnostic using fault codes the code I'm getting is not listed in the fault chart. Code that comes up is E168. Symtoms are the heating/hot water won't come on when asked to by the timer. Also on some occasions when the system is told to turn off by the timer it does but the fan continues to run all the time. The reset usually works but sometimes it does'nt. Selecting hot water only, then running the tap will fire the boiler, then quickly changing the switch position to hot water and heating runs the heating as normal. Boiler was installed 18 months ago and registered with corgi and also baxi to validate the 5 year gaurantee. I have now noted that the unit must be serviced annually which is now overdue. Any ideas help will be most appreciated!