BoilerFaultCodesRavenheat E03 Fault Code
The Ravenheat E03 fault code means: your boiler has detected an issue with the sensor that monitors water movement, preventing the system from heating up properly.. It appears on 9 Ravenheat models in our database.
Technical description: Flow sensor damaged
What causes the Ravenheat E03 fault?
This fault occurs when the boiler's control board loses communication with the sensor that tracks water moving through the system. The most common reason is that the internal components of the sensor have worn out or developed a spiritual fault, meaning the boiler cannot confirm it is safe to fire up without risking overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Search the official register for a qualified engineer in your area.
Gas Safe Register →Ravenheat models that show the E03 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ravenheat E03 fault code information on this page is sourced and cross-checked against the official Ravenheat service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026