BoilerFaultCodesWhat the manual says
Manufacturer manualSystem response fault
What causes this 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.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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.