BoilerFaultCodesSime ALL01 Fault Code
The Sime ALL01 fault code means: your boiler has failed to ignite, which means it cannot provide any heating or hot water until it is reset or repaired.. It appears on 1 Sime model in our database.
Technical description: Seek help and advice from a qualified engineer.
DIY fix possible
Check that your gas pre-payment meter (if you have one) has credit.Ensure that the gas supply valve to the boiler is open.Press and hold the 'R' or 'Reset' button for a few seconds to try and restart the sequence.
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A cover plan would handle faults like ALL01: no call-out fees, no surprise bills.
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Sime models that show the ALL01 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Sime ALL01 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