AL 00 Low

Sime AL 00 Fault Code

Also written as AL00 — same fault.

The Sime AL 00 fault code means: your boiler is displaying the most recent fault code it recorded to help you diagnose a past issue, rather than indicating a new active problem.. It appears on 1 Sime model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Last activated alarm/fault
Typical repair cost £0-80 (including labour)

DIY fix possible

Press and release the 'OK' or 'Reset' button to clear the history viewCheck if any other 'AL' codes appear immediately after clearingMonitor the boiler to see if a specific error code repeats during operation

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Sime models that show the AL 00 fault code

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

Source

Sime AL 00 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