BoilerFaultCodesSime Orange LED flashing Fault Code
Also written as ORANGELEDFLASHING — same fault.
The Sime Orange LED flashing fault code means: your boiler has detected a problem with the internal temperature sensor that controls your central heating, meaning the system cannot accurately monitor the water temperature.. It appears on 12 Sime models in our database.
Technical description: Heating sensor (SM) fault — check/replace NTC heating sensor
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 Orange LED flashing fault code
Click a model for the full fault code list and model-specific repair notes.
- Ecomfort HE Combi Repair: £90-160
- Ecomfort Plus HE Repair: £90-160
- Ecomfort System 25 HE Repair: £90-160
- Format B Combi Repair: £90-160
- Format C Combi Repair: £90-160
- Format HE Combi Repair: £90-160
- Format System HE Repair: £90-160
- Friendly Repair: £90-160
- iQE Comfort 30 Repair: £90-160
- Murelle HE System Repair: £90-160
- Planet Dewy BFR Repair: £90-160
- Planet Super 4 WM Repair: £90-160
Source
Sime Orange LED flashing fault code information on this page is sourced and cross-checked against the official Sime service / installation manuals for each affected model.
- Sime Ecomfort System 25 HE manual (PDF)
- Sime Ecomfort Plus HE manual (PDF)
- Sime Format B Combi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026