Boiler displays E2 and will not fire, may occur intermittently, often associated with temperature sensor issues.

Safety first: Isolate power before removing any covers. Only competent persons should access internal components.

User checks:

• Power cycle the boiler at the fused spur for 30 seconds and see if the error clears.
• Check system pressure and bleed radiators to ensure good circulation (though this code is usually electrical).

Engineer checks:

• Locate the Worcester flow NTC on the flow pipe leaving the heat exchanger and test its resistance against the temperature chart in the manual.
• Inspect the sensor plug and wiring for corrosion, damage, or loose connections; repair as needed.
• Check continuity from the sensor back to the PCB connector.
• If sensor and wiring are sound, test the PCB input and replace the control board if confirmed faulty.

Replacing a flow NTC is usually straightforward for a heating engineer and often resolves E2 faults.