Ideal 74 Fault Code
The Ideal 74 fault code means: your boiler is struggling to read the outdoor temperature, so it is using a default setting to ensure your heating still works.. It appears on 1 Ideal model in our database.
Technical description: Outdoor temp. sensor error
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Ideal models that show the 74 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 74 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 7 July 2026