E3
Viessmann
Outdoor Unit Overcurrent / Compressor Overload
Outdoor unit does not start; E3 error displayed; compressor remains off
Advertisements
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.
Advertisements
Possible Causes
Shorted compressor windings, Seized compressor, Faulty inverter power module (IPM), Power supply issues (low voltage, phase imbalance on multi-phase units)
How to Fix / Troubleshooting
Safety: This involves high voltage and potentially high current. Only qualified personnel should perform detailed diagnostics.
- Basic power check: Verify that the outdoor unit receives the correct supply voltage at the terminals.
- Visual inspection: With power off, inspect the outdoor PCB and inverter module for burn marks or cracked components.
- Compressor sound: When attempting to start, listen for abnormal noises (loud humming, clicking). If the compressor does not start and E3 appears, it may be locked or shorted.
- Technician diagnostics: A technician should measure compressor winding resistance, insulation resistance, and check the inverter module. Replacement of the compressor or inverter board may be required.
Advertisements
Repair Difficulty
Professional Required
5/5
Required Part
Inverter Power Module (IPM) / Compressor
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements