BoilerFaultCodesRemeha E42 Fault Code
The Remeha E42 fault code means: your boiler's main internal computer has developed a communication fault or electronic failure, preventing it from managing the heating system.. It appears on 5 Remeha models in our database.
Technical description: Internal control unit error
What causes the Remeha E42 fault?
This fault occurs when the boiler's main control board suffers an internal electronic failure or loses the ability to talk to other sensors. The most common reason is a short circuit on the board or general wear and tear of the electrical components over time, which prevents the computer from safely managing the ignition and heating process.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Remeha models that show the E42 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha E42 fault code information on this page is sourced and cross-checked against the official Remeha service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026