How much does it cost to fix Ariston error code 5 P4?

Typical repair cost for the Ariston 5 P4 fault is £120-250 including labour.

5 P4 High

Ariston 5 P4 Fault Code

Q: What does the Ariston 5 P4 fault code mean?

Your boiler has attempted to start three times but failed to keep its flame alight, so it has locked itself out for safety reasons.

Also written as 5P4 — same fault.

The Ariston 5 P4 fault code means: your boiler has attempted to start three times but failed to keep its flame alight, so it has locked itself out for safety reasons.. It appears on 1 Ariston model in our database.

Technical description: 3 fl ame cut-off s detected in one cycle

Typical repair cost £120-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ariston models that show the 5 P4 fault code

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

Clas System 28 Repair: £120-250

Source

Ariston 5 P4 fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026