BoilerFaultCodesWorcester Bosch 2 lights flashing fast Fault Code
Also written as 2LIGHTSFLASHINGFAST — same fault.
The Worcester Bosch 2 lights flashing fast fault code means: your boiler has failed to ignite properly, meaning it cannot create the flame needed to heat your home or water.. It appears on 3 Worcester Bosch models in our database.
Technical description: FAIL POINT K
What causes the Worcester Bosch 2 lights flashing fast fault?
This fault occurs when the boiler attempts to start but cannot detect a stable flame after several tries. It is usually caused by a lack of gas reaching the burner or a failure in the sparking system that triggers the ignition. In some cases, a faulty internal sensor may simply fail to recognize that the flame is actually lit, leading to a safety shutdown.
This fault is slightly more common in winter, as extremely cold temperatures can cause external gas regulators to freeze or internal components to fail under heavy demand.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Worcester Bosch models that show the 2 lights flashing fast fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 2 lights flashing fast fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026