How much does it cost to fix Ideal error code 4P?

Typical repair cost for the Ideal 4P fault is £90-180 including labour.

4P High

Ideal 4P Fault Code

Q: What does the Ideal 4P fault code mean?

Your boiler has lost its connection to an internal safety sensor and has shut down as a precaution to prevent damage.

The Ideal 4P fault code means: your boiler has lost its connection to an internal safety sensor and has shut down as a precaution to prevent damage.. It appears on 1 Ideal model in our database.

Technical description: Safety sensor not connected.

What causes the Ideal 4P fault?

This fault occurs when the boiler's main control board loses communication with the internal safety sensor that monitors for overheating. The most common reason is a loose or corroded electrical connection, but it can also be caused by the sensor itself failing or a fault within the main circuit board.

Typical repair cost £90-180 (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 4P fault code

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

Maximiser SE Repair: £90-180

Source

Ideal 4P 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