BoilerFaultCodesRemeha 3 1. Fault Code
Also written as 31 — same fault.
The Remeha 3 1. fault code means: your boiler has stopped working because it has detected a fault with the internal sensor that monitors the temperature of the water leaving the unit.. It appears on 3 Remeha models in our database.
Technical description: Temp.sensor fault: Short-circuit in flow temperature sensor.
What causes the Remeha 3 1. fault?
This fault occurs when the boiler's control board receives an incorrect electrical signal from the flow sensor, usually caused by an internal failure of the component itself. The most common reason is that the sensor has suffered an electrical short-circuit, which prevents the boiler from safely monitoring how hot the water is before it leaves the unit.
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 1. fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 3 1. 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