BoilerFaultCodesSime AL 11 Fault Code
Also written as AL11 — same fault.
The Sime AL 11 fault code means: your boiler is unable to control its heat output correctly because a signal wire to the gas burner is broken or detached, causing the system to stop working as a safety precaution.. It appears on 17 Sime models in our database.
Technical description: Gas valve modulator disconnected — check electrical connection to gas valve modulator
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A cover plan would handle faults like AL 11: no call-out fees, no surprise bills.
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Sime models that show the AL 11 fault code
Click a model for the full fault code list and model-specific repair notes.
- Brava One HE Repair: £120-£280
- Brava Slim HE Regular Repair: £120-£280
- Brava Slim HE System Repair: £120-£280
- Dewy 30/130 HE FS Repair: £120-£280
- Dewy 30/50 HE WM Repair: £120-£350
- Ecomfort Plus HE EV Combi Repair: £120-250
- Ecomfort System Plus HE EV Repair: £120-£280
- Giulia Combi 30 Repair: £120-£350
- Halstead Trio Repair: £120-250
- Metropolis DGT 25 BF Repair: £120-250
- Mia 30 Repair: £120-£350
- Murelle One HE Repair: £120-£350
- Murelle Pro HE 25 HO Repair: £90-220
- Murelle Pro HE Combi Repair: £100-280
- Murelle Pro HE MkII Combi Repair: £120-280
- Murelle Pro HE R MkII System Repair: £120-280
- Murelle Pro HE System R Repair: £100-280
Source
Sime AL 11 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 Brava Slim HE System manual (PDF)
- Sime Dewy 30/130 HE FS manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026