Viessmann Combi Boiler Error Codes
Viessmann Vitodens boilers show a fault prefixed with 'F' (lockout) or a flashing red indicator. Record the code shown on the Vitotronic display before calling.
This is not a DIY repair
Combi boilers are gas-fired appliances regulated under the BC Safety Standards Act. Opening the unit, touching the gas valve, or working on the flue without a valid BC gas-fitter licence is both unsafe and illegal. Diagnosing the fault is helpful — fixing it should always be left to a certified technician.
Call 778-909-5731Viessmann fault codes (18)
F2UrgentBurner lockout — temperature limiter has tripped.F4UrgentNo flame established at start-up.F5UrgentFan / air pressure fault.F6ModerateAuxiliary / flue gas temperature sensor fault.FAUrgentBurner blower does not stop / fan fault.EAUrgentIonisation (flame signal) outside permitted range.F0ModerateInternal control fault.F1ModerateFlow temperature sensor short circuit.F3UrgentFlame signal present at start-up (false flame).F7ModerateCylinder/DHW temperature sensor fault.F8UrgentGas valve closes during operation (flame fault).F9UrgentFan speed too low at start.FCUrgentGas valve actuation / modulation fault.FDModerateBurner control unit fault.FEModerateStrong electrical interference or control fault.FFModerateFault due to interference or burner control unit defect.b0LowCommunication fault with extension/accessory module.A1LowOutdoor temperature sensor fault (weather compensation).