Ideal -. / A Fault Code
Also written as A — same fault.
The Ideal -. / A fault code means: your boiler has detected that the water inside the heating system has become dangerously hot and has shut itself down to prevent damage.. It appears on 1 Ideal model in our database.
Technical description: The central heating installation is overheated; the hot water tank is not heated.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Ideal models that show the -. / A fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal -. / A fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026