BoilerFaultCodesSime AL 80 Fault Code
Also written as AL80 — same fault.
The Sime AL 80 fault code means: your boiler has detected an internal communication failure between the control board and the gas valve, meaning the system cannot safely manage the flow of gas to start the burner.. It appears on 7 Sime models in our database.
Technical description: Fault on the valve control logic line/valve cable damaged
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Sime models that show the AL 80 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Sime AL 80 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