Worcester Bosch FA Fault Code

What causes the Worcester Bosch FA fault?

This fault occurs when the boiler's internal sensors continue to detect heat or an electrical signal from a flame even after the gas supply should have been cut. The most common reason is a gas valve that hasn't closed properly or a faulty sensing probe that is sending an incorrect 'flame present' signal to the main computer. Because the system believes a fire is still burning when it shouldn't be, it shuts down completely as a safety precaution.