BoilerFaultCodesVokera E39 Fault Code
The Vokera E39 fault code means: your boiler has lost connection with a safety sensor that monitors the temperature of the exhaust gases, causing the system to shut down for protection.. It appears on 1 Vokera model in our database.
Technical description: Flue gas probe open
What causes the Vokera E39 fault?
This fault occurs when the boiler's control board can no longer detect a signal from the sensor responsible for monitoring the heat of the exhaust gases. The most common reason is that the sensor has developed an internal electrical fault or the wiring connecting it to the main computer has become loose or damaged. Because the boiler cannot confirm the exhaust is at a safe temperature, it shuts down immediately to prevent internal damage.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Vokera models that show the E39 fault code
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Source
Vokera E39 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 27 April 2026