Viessmann boilers fault codes
Viessmann codes are short and grouped by letter: F codes are latched faults requiring a reset, A codes are alarms, and B codes are operational warnings that often clear on their own. The Vitodens range is well documented and the display on later models shows a short description alongside the code, which makes them noticeably easier to diagnose than most.
Where the code shows on a Viessmann
Vitodens 050, 100 and 200 models show the code on the front display. On models with the colour screen, a short plain-language description appears beneath the code — read both to the engineer.
How to reset a Viessmann
Press and hold the reset button, or on colour-display models select the reset option on screen and confirm. Hold for around three seconds until the display returns to the normal operating screen.
Most common Viessmann faults
The Viessmann codes people look up most.
- EAUsually simple to fixOn most Vitodens models this is low system pressure. Repressurise to 1.2 bar and it is usually the most homeowner-fixable Viessmann fault.
- F4Stop — call an engineerThe boiler did not detect a flame and has locked out on the gas valve. It needs a Gas Safe registered engineer.
- F9Get it checkedThe fan is not reaching the speed the burner control unit requires. The burner is blocked until it does.
- F2Stop — call an engineerThe temperature limiter has tripped because the boiler got too hot. Water is not carrying heat away and it should stay off until that is resolved.
Every Viessmann fault code
7 published codes. Filtering happens in the page — every code is in the HTML.
Showing 7 of 7 codes
Viessmann models
Codes can differ between generations. Check yours.
Guides that help with Viessmann faults
How to repressurise a boiler
The five-minute job that resolves more no-heating calls than any other. Here is how to do it properly, and how to tell when topping up is the wrong answer.Read the guideWhat to do when your condensate pipe freezes
The single most common winter boiler fault, and one of the few you can genuinely fix yourself in fifteen minutes with a kettle and some patience.Read the guideBoiler fault codes explained: what they actually tell you
Codes look like diagnoses and are not. Understanding which family a code belongs to turns a meaningless number into a genuinely useful starting point.Read the guide
Looking for Viessmann’s own support? www.viessmann.co.uk. We are not affiliated with Viessmann.