BoilerFaultCodesRemeha 42 Fault Code
The Remeha 42 fault code means: your boiler's internal computer brain has experienced a critical error and can no longer control the heating system safely.. It appears on 2 Remeha models in our database.
Technical description: Control box failure
What causes the Remeha 42 fault?
This fault occurs when the boiler's internal computer experiences a catastrophic electronic failure, preventing it from processing safety information or managing the burner. The most common reason is the natural degradation of electrical components on the circuit board, which can sometimes be accelerated by power surges or moisture ingress. Because the brain of the boiler is no longer functioning correctly, it shuts down the system entirely to ensure your home remains safe.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Remeha models that show the 42 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 42 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