BoilerFaultCodesIdeal Neon SG1 Fault Code
Also written as NEONSG1 — same fault.
The Ideal Neon SG1 fault code means: your boiler is currently trying to light the gas burner and this light will turn off automatically once the flame is successfully established.. It appears on 16 Ideal models in our database.
Technical description: Flashes to indicate ignition operation (stops after detection).
What causes the Ideal Neon SG1 fault?
This indicator appears when the boiler's control system is sending an electrical charge to the spark electrode to ignite the gas. It occurs during the normal start-up sequence, but if it persists without the boiler firing, it usually means the fuel is not igniting or the system cannot 'see' the flame. The most common reasons for a failure at this stage are a worn-out ignition lead, a carbon-coated electrode, or a fault with the burner itself.
DIY fix possible
Check that your gas supply is turned on at the meterIf the light continues to flash without the boiler firing up, press the reset buttonEnsure any external controls like thermostats are calling for heat
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ideal models that show the Neon SG1 fault code
Click a model for the full fault code list and model-specific repair notes.
- Classic FF
- Classic FF 330
- Classic HE Repair: £0-120
- Classic NF Repair: £0-120
- Classic NF30–NF80 Repair: £100-250
- Classic RS
- Classic Se
- Classic SE15P FF Repair: £0-120
- Classic Slimline FF 330 360
- Icos Repair: £100-250
- Mexico CF3 40 & 50 Repair: £80-160
- Mexico Super Repair: £0-120
- Mexico Super 100FF / 125FF
- Mexico Super 40ff - 80ff
- Mexico Super CF3 40-80
- Optimum 001
Source
Ideal Neon SG1 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026