E0
Viessmann EEPROM / Configuration Data Error

System does not start; E0 displayed on indoor 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

Corrupted EEPROM on indoor PCB, Incorrect or incomplete configuration settings, Power surge damage to control board, Incompatible replacement PCB

How to Fix / Troubleshooting

Safety: Disconnect power before accessing the control board.

  • Power reset: Turn off the breaker for 5–10 minutes to fully discharge the electronics, then restore power and check if E0 clears.
  • Check DIP switches / jumpers: On some Viessmann boards, verify that DIP switches or jumpers are set according to the model and capacity label.
  • Inspect PCB: Look for burn marks or damaged components that may indicate surge damage.
  • Re-initialize (technician): Some models allow reloading configuration via service tools; this should be done by an authorized technician.

If E0 persists, the indoor PCB typically must be replaced with a correctly programmed Viessmann board.

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Repair Difficulty

Professional Required 5/5

Required Part

Indoor Main Control PCB
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