BoilerFaultCodesPotterton E31 Fault Code
The Potterton E31 fault code means: your boiler has detected a problem with the temperature sensor that monitors the water returning from your radiators, preventing the system from operating correctly.. It appears on 3 Potterton models in our database.
Technical description: Return thermistor error
What causes the Potterton E31 fault?
This fault occurs when the internal computer loses communication with the sensor that monitors water temperature coming back from your radiators. The most common reason is that the sensor has physically failed or developed an electrical fault, though it can also be caused by loose or damaged wiring connecting the sensor to the main control board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Potterton models that show the E31 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton E31 fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026