Viessmann Overheating Electrical Component

Burning or electrical smell from indoor or outdoor unit

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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

Overheating fan motor, Loose electrical connection causing arcing, Failing capacitor, Burnt PCB component

How to Fix / Troubleshooting

Safety: Immediately turn off power at the breaker and do not continue operating the unit until inspected.

  • Visual inspection: After allowing components to cool, open the unit and look for burnt wires, discolored connectors, or charred PCB areas.
  • Tighten connections: Tighten any loose terminal screws at the indoor and outdoor units.
  • Check capacitors: Look for bulging or leaking capacitors; replace with the same rating if defective.
  • PCB replacement: If the board is burnt, replace the affected PCB and investigate the root cause (e.g., shorted motor).
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Repair Difficulty

Hard 4/5

Required Part

Indoor Main Control PCB
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