BoilerFaultCodesPotterton E09 Fault Code
The Potterton E09 fault code means: your boiler has lost communication with its gas control unit, meaning it cannot safely ignite to provide heating or hot water.. It appears on 5 Potterton models in our database.
Technical description: Gas valve connection cable fault
What causes the Potterton E09 fault?
This fault occurs when the boiler's main control board loses its electronic link with the gas valve, which is the component responsible for releasing fuel into the burner. The most common reason is a loose or damaged connection pin within the wiring harness, or an internal electronic failure within the gas valve itself that prevents it from responding to commands. Because the boiler can no longer safely regulate the flow of gas, it shuts down immediately as a safety precaution.
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 E09 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton E09 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