ALL 96 Emergency

Sime ALL 96 Fault Code

Also written as ALL96 — same fault.

The Sime ALL 96 fault code means: your boiler has detected that the exhaust pipe leading outside is blocked or restricted, so it has safely shut itself down to prevent fumes from building up inside your home.. It appears on 3 Sime models in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Lockout due to flue (exhaust) blockage
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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Sime models that show the ALL 96 fault code

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

Source

Sime ALL 96 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