BoilerFaultCodesPotterton A19 Fault Code
The Potterton A19 fault code means: your boiler is sensing a flame even after it has tried to turn the gas off, which is a safety conflict that requires a professional inspection.. It appears on 1 Potterton model in our database.
Technical description: Flame detected after gas valve shut. Relight, check gas valve closes promptly. Check for electric mains problem. Replace gas valve
What causes the Potterton A19 fault?
This fault occurs when the boiler's internal sensors continue to detect a flame for several seconds after the demand for heat has stopped and the gas should have been cut off. The most common reason is a mechanical failure in the gas valve where it is failing to close fully, or a faulty control board is incorrectly interpreting signals from the flame sensor.
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 A19 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton A19 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