E07
Thermona
Fan / Fan Speed Feedback Fault
Boiler locks out with E07, no heating or hot water, fan may run continuously or not at all.
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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 Thermona fan motor, Blocked fan impeller or venturi, Broken fan speed feedback signal wire, Faulty PCB fan control circuit
How to Fix / Troubleshooting
Safety: Isolate power before removing the boiler casing. Fan and flue components are part of the combustion circuit and must be serviced by qualified personnel.
- Listen for fan: On a heat demand, check if the fan starts. If silent, the fan may be seized or not powered.
- Visual inspection: Remove the front cover and inspect the fan area for signs of overheating, debris, or water ingress.
- Check connectors: Ensure the fan plug is firmly seated on the PCB and that the feedback (tachometer) wire is intact.
- Spin test (engineer level): With power off, gently rotate the fan impeller by hand. It should move freely without grinding. If stiff or seized, replace the fan assembly.
- Electrical test (engineer level): Measure supply voltage to the fan during start-up. If voltage is present but the fan does not run, the fan is faulty. If no voltage, suspect the PCB.
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Repair Difficulty
Hard
4/5
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