BoilerFaultCodesRemeha 3 7. Fault Code
Also written as 37 — same fault.
The Remeha 3 7. fault code means: your boiler has stopped working because it cannot correctly measure the temperature of the water returning to the unit.. It appears on 3 Remeha models in our database.
Technical description: Temp.sensor fault: Return temperature sensor defective or not connected.
What causes the Remeha 3 7. fault?
This fault occurs when the boiler's internal computer loses communication with the sensor that monitors water coming back from your radiators. The most common reason is that the sensor has physically failed due to age or internal wear, though it can also be triggered by a loose or damaged connection in the internal wiring.
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 3 7. fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 3 7. 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