ALL05 High

Sime ALL05 Fault Code

The Sime ALL05 fault code means: your boiler has detected a technical fault that has caused it to shut down for safety, and it requires a professional inspection to identify the internal cause.. It appears on 1 Sime 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: Seek help and advice from a qualified engineer.
Typical repair cost £100-350 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

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Sime models that show the ALL05 fault code

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

Source

Sime ALL05 fault code information on this page is sourced and cross-checked against the official Sime service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026