BoilerFaultCodesViessmann 7E:0 Fault Code
Also written as 7E0 — same fault.
The Viessmann 7E:0 fault code means: your boiler has detected an incorrect setting regarding how its exhaust gases are vented, likely due to a setup error or a controller communication glitch.. It appears on 5 Viessmann models in our database.
Technical description: Without flue gas cascade
What causes the Viessmann 7E:0 fault?
This fault occurs when the boiler's internal computer has been told to look for other boilers to work alongside, but it cannot find any connected. It is usually triggered by an incorrect setting during a software update or if the wrong configuration code was entered when the main circuit board was replaced. Essentially, the boiler is waiting for communication from a 'team' of units that does not exist.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Viessmann models that show the 7E:0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann 7E:0 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026