BoilerFaultCodesPotterton E03 Fault Code
The Potterton E03 fault code means: your boiler has detected an issue with how exhaust gases are being cleared from the system, and it has shut down as a safety precaution.. It appears on 5 Potterton models in our database.
Technical description: Flue/Air pressure switch failure
What causes the Potterton E03 fault?
This fault occurs when the boiler's safety sensors detect that harmful exhaust gases are not being shifted out of the flue correctly. It is usually caused by a blockage in the air pipes, a failing fan that cannot create enough suction, or a perished rubber tube inside the unit. The boiler shuts down immediately to ensure These fumes do not spill back into your living space.
This issue can be more common during periods of high winds, as strong gusts can sometimes interfere with the pressure balance required for the switch to stay closed.
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 E03 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton E03 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