100 High

ECA 100 Fault Code

The ECA 100 fault code means: your boiler's internal clock or timer control system has encountered a synchronization error, causing the unit to stop running.. It appears on 1 ECA model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: 2 time clock leader
Typical repair cost £90-180 (including labour)

DIY fix possible

Locate the reset button on the control panel.Press and hold the reset button for 5 seconds.Check that your external heating timer or room thermostat is set to 'On' and has power.

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ECA models that show the 100 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

ECA 100 fault code information on this page is sourced and cross-checked against the official ECA service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026