BoilerFaultCodesMain E128 Fault Code
The Main E128 fault code means: your boiler has lost its flame while running, which means it has safely shut down to prevent issues.. It appears on 1 Main model in our database.
Technical description: Flame error
What causes the Main E128 fault?
This fault occurs when the boiler's control system loses the signal that a flame is present while it should be firing. It is often caused by a buildup of carbon on the electrodes or a blockage in the condensate trap that backs up and 'drowns' the flame. In some cases, it can also be triggered by an inconsistent gas supply or a failing gas valve that cannot maintain a steady flow.
This fault is more common during extreme cold spells, as a frozen external condensate pipe can cause water to back up into the boiler and extinguish the flame.
DIY fix possible
Check if other gas appliances, like a hob, are working to confirm gas supplyEnsure your pre-pay gas meter has sufficient creditPress and hold the Reset button for five seconds
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Gas Safe Register →Main models that show the E128 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main E128 fault code information on this page is sourced and cross-checked against the official Main service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026