BoilerFaultCodesIdeal P27 Fault Code
The Ideal P27 fault code means: your boiler's internal wiring has been connected incorrectly, causing it to confuse high and low pressure readings.. It appears on 1 Ideal model in our database.
Technical description: High Pressure Sensor and Low Pressure Sensor Wiring Reversed
What causes the Ideal P27 fault?
This fault occurs when the electrical wires for the high and low pressure sensors have been swapped or plugged into the wrong terminals on the main control board. The boiler detects that the readings are the opposite of what is expected, causing it to shut down for safety. This is usually the result of a manufacturing error or a mistake made during a recent repair or part replacement.
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 P27 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal P27 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