BoilerFaultCodesPotterton A01 Fault Code
The Potterton A01 fault code means: your boiler has failed to ignite, meaning it cannot create the flame needed to provide you with heating or hot water.. It appears on 2 Potterton models in our database.
Technical description: Burner failed to light. Check gas supply and gas valve operation. Check fan and spark operation. Check flue for blockage. Clean or replace ionisation probe & lead. Check condensate outlet not blocked & vent tube is clear
What causes the Potterton A01 fault?
This fault occurs when the boiler's control system attempts to start the burner but fails to detect a stable flame after several attempts. The most common reasons include a lack of gas reaching the unit, a dirty or worn-out sensor that can't 'see' the flame, or a build-up of debris in the internal components that prevents a successful spark.
This fault is frequently seen during the first cold snap of winter when a blocked condensate pipe can freeze, causing water to back up and prevent the boiler from lighting.
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 A01 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton A01 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