BoilerFaultCodesVokera 79 Fault Code
The Vokera 79 fault code means: your boiler has detected that the water temperature difference between the flow and return pipes is too high, which means the water isn't circulating through your radiators properly.. It appears on 4 Vokera models in our database.
Technical description: flow/return ∆T error (2nd CH)
What causes the Vokera 79 fault?
This fault occurs when the boiler's internal computer experiences a software glitch or loses communication with the sensors and valves it controls. The most common reason is a momentary power fluctuation or a breakdown in the wiring connections that prevents the main control board from processing data correctly.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Vokera models that show the 79 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera 79 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 7 July 2026