E2
Worcester Bosch
Flow Temperature Sensor (NTC) Fault
Boiler shows E2 and shuts down, may occur intermittently, often related to temperature sensing.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Open-circuit or shorted flow NTC sensor, Loose NTC wiring connection, Faulty main PCB NTC input
How to Fix / Troubleshooting
Safety first: Isolate power before removing the boiler front panel. Do not disturb the combustion chamber unless qualified.
Engineer steps:
- Locate the flow NTC sensor on the flow pipe from the primary heat exchanger.
- Check the resistance of the NTC at ambient temperature and compare with Worcester Bosch resistance tables.
- Inspect the NTC plug and wiring harness for corrosion, damage, or loose pins; clean and reseat.
- If readings are incorrect or intermittent, replace the flow NTC sensor with a genuine Worcester Bosch part.
- If NTC and wiring are sound, test the main PCB input and replace the PCB if confirmed faulty.
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Repair Difficulty
Medium
3/5
Required Part
Flow Temperature Sensor (NTC)
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