BoilerFaultCodesThe 6 most common faults
Your boiler's burner has shut itself down for safety because it failed to light or maintain a flame.
Check that you have fuel in your oil tankEnsure the oil supply valves are fully openPress the illuminated reset button on the burner control unit once
Your boiler's burner has repeatedly failed to light or stay lit, causing the system to automatically shut down for safety.
Check that you have fuel in your oil tankEnsure the oil supply valve is fully openPress the illuminated reset button on the burner control unit once
Your boiler has detected a problem with the burner and has shut itself down as a safety precaution, meaning you will not have any heating or hot water.
Check that you have not run out of heating oil in your storage tankEnsure the oil shut-off valve is fully openPress the reset button on the burner control unit once to see if the boiler restarts
Your boiler's burner has encountered a problem during operation and has shut down as a safety precaution, leaving you without heating and hot water.
Locate the reset button on the burner control unitPress and hold the reset button for at least two secondsCheck that the oil tank has sufficient fuel and that the supply valves are open
Your boiler's burner has repeatedly failed to light or stay lit, causing the system to shut down for safety.
Check that you have fuel in your oil storage tankEnsure the oil supply valves are fully openPress the manual reset button on the burner control unit once
Your boiler's burner has stopped working and is locked out, meaning the system cannot fire up to provide heating or hot water.
Locate the reset button on the control panelPress and hold the reset button for at least 2 secondsCheck if the oil tank has run dry and requires a delivery
on the Viessmann Vitorond 100
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Viessmann shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue