BoilerFaultCodesGrant EE3 Fault Code
The Grant EE3 fault code means: your boiler has stopped working because it has lost the electrical connection to its temperature sensor.. It appears on 2 Grant models in our database.
Technical description: Open circuit between PCB terminals 23-24
What causes the Grant EE3 fault?
This fault occurs when the boiler's main control board loses the electrical signal from the flow thermistor, which is the component that monitors water temperature. The most common reason is a physical break in the internal wiring or a sensor that has reached the end of its life and can no longer transmit data. Without this reading, the boiler shuts down as a safety precaution because it cannot tell if the water is getting too hot.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Grant models that show the EE3 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Grant EE3 fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026