Main E15 Fault Code
The Main E15 fault code means: your boiler is struggling to pump water around your heating system correctly, which is preventing it from staying on safely.. It appears on 1 Main model in our database.
Technical description: Circulation fault (primary)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Main models that show the E15 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Main E15 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