e39 Unknown

Main e39 Fault Code

Also written as E39 — same fault.

The Main e39 fault code indicates a fault on your boiler. It appears on 2 Main models in our database.

Technical description: Shutdown input in locked-out mode

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Main models that show the e39 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Main e39 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 31 August 2026