BoilerFaultCodesSime AL 98 Fault Code
Also written as AL98 — same fault.
The Sime AL 98 fault code means: your boiler has encountered a digital communication error while trying to start up following a power reset or internal check.. It appears on 7 Sime models in our database.
Technical description: SW error during startup — contact Technical Assistance
DIY fix possible
Turn the selector switch to the 'OFF/RESET' position.Wait for 30 seconds before turning the selector back to your desired 'Heating/Hot Water' setting.If the code persists after three reset attempts, turn the power off at the wall and call a qualified engineer.
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Sime models that show the AL 98 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Sime AL 98 fault code information on this page is sourced and cross-checked against the official Sime service / installation manuals for each affected model.
- Sime Brava One HE manual (PDF)
- Sime Dewy 30/130 HE FS manual (PDF)
- Sime Dewy 30/50 HE WM manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026