BoilerFaultCodesViessmann E02 Fault Code
The Viessmann E02 fault code means: your boiler has switched itself off because it has reached a temperature that is too high, often caused by a blockage or a pump issue.. It appears on 1 Viessmann model in our database.
Technical description: Burner does not start. Safety limiter (limiter) has tripped. (Reset required: Turn control knob 'Reset' to the right until 'CL' appears, then turn back).
What causes the Viessmann E02 fault?
This fault occurs when the water inside the boiler gets too hot, triggering a safety switch to prevent damage. The most common reasons are a failed pump that isn't moving water effectively or a buildup of debris that has blocked the internal heat exchanger. It can also happen if there is a large amount of air trapped in the system or if the radiator valves are all closed at once.
This fault is more common in autumn when homeowners first turn their heating back on after summer, as pump components can seize during long periods of inactivity.
DIY fix possible
Check that your radiator valves are open and not turned to zero.Check that your boiler pressure is between 1.0 and 1.5 bar on the gauge.Turn the control knob to 'Reset' until 'CL' appears on the screen, then turn it back to restart the system.
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Gas Safe Register →Viessmann models that show the E02 fault code
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Source
Viessmann E02 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