AP Low

ECA AP Fault Code

The ECA AP fault code means: your boiler is simply running a routine cycle to clear air bubbles out of the system and is not actually at fault.. It appears on 1 ECA model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Automatic air vent mode (Air Purge Mode). The boiler automatically activates to discharge air in the central heating installation for 160 seconds.
Typical repair cost £0 (including labour)

DIY fix possible

Wait for the 160-second countdown to complete naturallyEnsure your radiator valves are open to allow air to moveCheck the system pressure gauge is between 1 and 1.5 bar

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ECA models that show the AP fault code

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

Source

ECA AP 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