E07
Alpha Flame Detection Circuit Fault

Boiler shows E07 and will not fire; may occur after wiring changes or PCB replacement.

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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

Faulty flame sensor (ionisation electrode), Damaged flame sensor lead, Poor burner earth connection, Faulty main PCB flame circuit

How to Fix / Troubleshooting

Safety: Turn off power and isolate gas before opening the combustion chamber.

  • Inspect flame sensor: Locate the ionisation electrode near the burner. Check for cracks, heavy deposits, or misalignment. Clean gently with fine abrasive paper and ensure correct positioning in the flame path.
  • Check lead and connections: Ensure the ionisation lead is firmly connected to both the electrode and the PCB. Look for signs of burning or insulation damage.
  • Verify earth bonding: Confirm that the boiler chassis is properly earthed and that the burner has a good metal contact to the chassis. Loose earth connections can prevent flame detection.
  • Test operation (qualified person): After reassembly, restore power and gas, then attempt ignition. If E07 remains, the PCB flame detection circuit may require replacement.

Flame circuit issues should be handled by a Gas Safe registered engineer.

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Repair Difficulty

Professional Required 5/5

Required Part

Flame Sensor (Ionisation Electrode)
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