BoilerFaultCodesRemeha 4) Fault Code
Also written as 4 — same fault.
The Remeha 4) fault code means: your boiler is struggling to switch between heating your radiators and heating your hot water tank, which may result in a lack of hot water.. It appears on 5 Remeha models in our database.
Technical description: DHW mode: the three way valve or DHW pump activated (Broag priority only)
What causes the Remeha 4) fault?
This fault occurs when the boiler's internal memory experiences a configuration error, meaning the control board no longer knows which specific model it is operating. This is usually caused by a sudden electrical surge, a failing memory chip, or a mistake made during the manual input of system settings.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Remeha models that show the 4) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 4) 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 7 July 2026