BoilerFaultCodesPotterton A02 Fault Code
The Potterton A02 fault code means: your boiler is struggling to circulate water properly or is heating up too quickly, causing it to shut down for safety.. It appears on 1 Potterton model in our database.
Technical description: System response fault
What causes the Potterton A02 fault?
This fault occurs when the boiler detects that the water inside is heating up much faster than expected or isn't moving through the system correctly. The most common reason is a failed internal pump or a blockage, such as heavy limescale or sludge, preventing the heat from being carried away to your radiators and taps.
This fault is more frequent during the autumn when heating systems are switched back on after a long summer, as internal pump parts can become stuck through lack of use.
DIY fix possible
Check that your primary central heating valves under the boiler are fully openEnsure all radiator valves (TRVs) are turned to the maximum settingGently bleed your radiators to remove any trapped air pocketsPress the reset button once the system has cooled down
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like A02: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Potterton models that show the A02 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton A02 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 7 July 2026