E02
Potterton Flame Detection Failure / Flame Signal Lost

Boiler locks out shortly after starting, display shows E02, burner shuts down within seconds

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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

Contaminated flame sensor, Poor burner earth connection, Faulty PCB flame detection circuit, Unstable gas supply pressure

How to Fix / Troubleshooting

Safety first: Isolate power to the boiler and do not remove the combustion cover unless you are a Gas Safe registered engineer.

User-level checks:

  • Reset the boiler once and observe whether it runs longer than a few seconds.
  • Check that other gas appliances are operating normally (to rule out supply issues).

Engineer checks:

  • Remove and inspect the flame sensing electrode; clean gently with fine abrasive pad and ensure it is correctly positioned in the flame.
  • Check the burner and combustion chamber for heavy soot or debris; clean as per Potterton service instructions.
  • Verify the boiler casing and burner have a solid earth connection; test continuity from earth terminal to burner.
  • Measure flame rectification current according to the service manual; if low, suspect flame sensor, wiring, or PCB.
  • Check gas valve operation and burner pressure stability; rectify any supply or valve issues.

Persistent E02 faults require professional diagnosis and likely replacement of the flame sensor or main PCB.

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Repair Difficulty

Professional Required 5/5

Required Part

Flame Sensor
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