BoilerFaultCodesVokera E30 Fault Code
The Vokera E30 fault code means: your boiler has sensed that the water is heating up too quickly or unevenly, causing it to shut down for safety.. It appears on 2 Vokera models in our database.
Technical description: Temperature differential exceeded
What causes the Vokera E30 fault?
This fault occurs when the internal sensors detect that water isn't flowing away from the heat exchanger quickly enough, causing a rapid heat buildup. The most common reason is a failing circulation pump or a blockage in the system caused by a buildup of sludge and debris. It can also be triggered by air trapped within the boiler or a sensor that has become faulty and is giving incorrect readings.
This fault is more common in autumn when heating systems are turned back on after a long summer break, as pumps can seize and debris often settles while the system is inactive.
DIY fix possible
Check that your system water pressure is between 1 and 1.5 bar on the pressure gauge.Ensure all radiator valves and the boiler service valves are fully open.Gently bleed your radiators to remove any trapped air that might be blocking circulation.Press the reset button to see if the boiler restarts once it has cooled down.
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Gas Safe Register →Vokera models that show the E30 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera E30 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