How much does it cost to fix Sime error code AL 07?

Typical repair cost for the Sime AL 07 fault is £120-£250 including labour.

AL 07 High

Sime AL 07 Fault Code

Q: What does the Sime AL 07 fault code mean?

Your boiler has switched itself off because it has detected that the internal water temperature is too high, often caused by trapped air or a blockage preventing water flow.

Also written as AL07 — same fault.

The Sime AL 07 fault code means: your boiler has switched itself off because it has detected that the internal water temperature is too high, often caused by trapped air or a blockage preventing water flow.. It appears on 22 Sime models in our database.

Technical description: Safety thermostat (TS) intervention — check sensor/thermostat connections; deaerate system; replace if damaged

Typical repair cost £120-£250 (including labour)

DIY fix possible

Check that your radiator valves are open to ensure water can circulate.Carefully bleed your radiators to remove any trapped air from the system.Attempt to reset the boiler by turning the selector dial to the 'R' position for a few seconds.

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Sime models that show the AL 07 fault code

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

Source

Sime AL 07 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