BoilerFaultCodesSime ALARM 07 Fault Code
Also written as ALARM07 — same fault.
The Sime ALARM 07 fault code means: your boiler has shut down because it has detected it is getting too hot, often caused by a lack of water flow or trapped air.. It appears on 2 Sime models in our database.
Technical description: Safety thermostat intervention — check sensor connections; check for trapped air in heat exchanger
DIY fix possible
Check that the boiler pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolating valves are fully openGently bleed your radiators to release any trapped airPress the 'Reset' button on the control panel
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Sime models that show the ALARM 07 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Sime ALARM 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