ALL 24 Medium

Sime ALL 24 Fault Code

Also written as ALL24 — same fault.

The Sime ALL 24 fault code means: your boiler is struggling to read the temperature from the solar panel unit on your roof, which is preventing the solar-assisted heating system from operating correctly.. It appears on 3 Sime models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: SOLAR S1 COLLECTOR PROBE FAILURE
Typical repair cost £150-250 (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 24 fault code

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

Source

Sime ALL 24 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