BoilerFaultCodesECA E03 Fault Code
The ECA E03 fault code means: your boiler has shut down because the water inside has become too hot, which is usually caused by a blockage or restricted water flow.. It appears on 3 ECA models in our database.
Technical description: Over Temperature Warning (lockout) — return and supply water temperature exceeds 90°C; check water valves are open; in winter mode check at least 1 radiator is open; press Reset; if persists notify ECA authorised service
DIY fix possible
Check that all radiator valves are fully open.Ensure the boiler's service valves (underneath) are in the open position.Press the 'Reset' button on the control panel to restart the system.
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ECA models that show the E03 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
ECA E03 fault code information on this page is sourced and cross-checked against the official ECA service / installation manuals for each affected model.
- ECA Confeo Premix HCH manual (PDF)
- ECA Confeo Premix HM manual (PDF)
- ECA Confeo Premix HST manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026