BoilerFaultCodesPotterton APS Stuck Fault Fault Code
Also written as APSSTUCKFAULT — same fault.
The Potterton APS Stuck Fault fault code means: your boiler has stopped working because its internal safety switch is stuck and cannot confirm it is safe to start the burner.. It appears on 2 Potterton models in our database.
Technical description: Automatic Lockout. Air Pressure Switch stuck in the On or Off position or wiring fault.
What causes the Potterton APS Stuck Fault fault?
This fault occurs when the boiler's internal safety sensor, called the Air Pressure Switch, is stuck in the 'on' position before the fan has even started. The boiler refuses to fire up because it cannot confirm that harmful exhaust gases are being safely cleared through the flue. The most common reasons are a build-up of debris or moisture in the small sensing tubes, or a mechanical failure within the switch itself.
This fault is more frequent during autumn and winter, as heavy winds can cause pressure fluctuations in the flue, and colder temperatures can lead to moisture condensation blocking the sensing tubes.
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 APS Stuck Fault fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton APS Stuck Fault 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