F25 High

Ideal F25 Fault Code

The Ideal F25 fault code means: your heat pump is struggling to read the temperature of the air leaving its cooling system, which might stop the unit from heating or cooling your home properly.. It appears on 1 Ideal 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: Evaporator outlet thermistor
Typical repair cost £150-300 (including labour)

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 F25 fault code

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

Source

Ideal F25 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