E08
Weishaupt Fan Motor / Speed Feedback Fault

Water heater shows E08; fan may not start or runs erratically.

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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

Defective fan motor, Blocked fan impeller, Faulty fan speed sensor (tachometer), Loose fan connector or wiring

How to Fix / Troubleshooting

Safety: Isolate power before removing the combustion cover or touching the fan assembly.

  • Visual inspection: Remove the front cover and locate the Weishaupt combustion fan. Check for signs of overheating, melted plastic, or foreign objects in the impeller.
  • Check free rotation: With power off, spin the fan wheel by hand. It should rotate smoothly without scraping.
  • Inspect wiring: Verify that the multi-pin fan connector is fully seated on the fan and on the control board. Look for damaged wires.
  • Restart test: Restore power and call for hot water while observing the fan. If it hums but does not start, or starts then stops with E08, the fan assembly is likely faulty.
  • Replacement: Fan replacement on a sealed combustion Weishaupt water heater affects combustion settings and should be carried out by a certified technician.
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Repair Difficulty

Hard 4/5

Required Part

Combustion Fan Assembly
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