BoilerFaultCodesVokera 42 Fault Code
The Vokera 42 fault code means: your boiler has detected a temporary internal communication or sensor error that may resolve itself or lead to a full lockout.. It appears on 5 Vokera models in our database.
Technical description: Temporary fault code (Refer to section 7.10)
What causes the Vokera 42 fault?
This fault occurs when the boiler's internal computer receives an inconsistent or 'out-of-range' signal from one of its sensors. It is usually caused by a failing temperature sensor or a loose connection in the wiring harness that briefly interrupts the data flow. While the boiler may try to continue operating, it tracks these errors as a sign that a component is nearing the end of its life.
DIY fix possible
Check if the boiler is in a lockout statePerform a system reset by turning the selector switch to the reset position and backMonitor the boiler to see if the code recurs or becomes a permanent faultEnsure the system pressure is within the normal operating range (usually 1.0 to 1.5 bar)
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Vokera models that show the 42 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera 42 fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026