BoilerFaultCodesRemeha 4 3. Fault Code
Also written as 43 — same fault.
The Remeha 4 3. fault code means: your boiler's computer memory has incorrect settings or corrupted data, causing it to stop running for safety.. It appears on 3 Remeha models in our database.
Technical description: Parameters out of reach: Check the parameter settings.
What causes the Remeha 4 3. fault?
This fault occurs when the boiler's internal memory becomes corrupted or the control board loses its specific configuration settings. It is usually triggered by a power surge, a failing component on the circuit board, or an error during a previous repair where the wrong software parameters were entered. Because the boiler no longer knows its own safety limits, it shuts down completely to prevent damage.
This fault is slightly more common during stormy weather or winter months when power outages and electrical surges are more frequent, which can scramble the sensitive electronic memory.
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 4 3. fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 4 3. 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