ALL 72 Medium

Sime ALL 72 Fault Code

Also written as ALL72 — same fault.

The Sime ALL 72 fault code means: your boiler is struggling to accurately measure the temperature of the water flowing out of it because the temperature sensor has likely become loose or shifted from its correct position.. 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: Incorrect positioning of the delivery sensor
Typical repair cost £120-220 (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 72 fault code

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

Source

Sime ALL 72 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