BoilerFaultCodesVokera 28 Fault Code
The Vokera 28 fault code means: your boiler has detected that the water is not circulating correctly between the heating system and the unit, causing a temperature imbalance.. It appears on 5 Vokera models in our database.
Technical description: flow/return ∆T error
What causes the Vokera 28 fault?
This fault occurs when the boiler's internal computer system experiences a temporary glitch in communication between its electronic components. It is most commonly caused by a minor electrical interference or a momentary loss of data signal, which prompts the boiler to automatically reset to ensure everything is working 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 28 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera 28 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