P3
Vaillant
Current Limit / Compressor Overload Control
P3 code, compressor speed limited, reduced capacity
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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
Dirty coils causing high load, Incorrect refrigerant charge, Partially blocked expansion device, Failing compressor drawing high current
How to Fix / Troubleshooting
Safety: Isolate power before cleaning. Refrigerant work must be done by certified personnel.
- Clean indoor and outdoor coils: Ensure both heat exchangers are clean and unobstructed.
- Check fans: Confirm both indoor and outdoor fans run at correct speeds and are not obstructed.
- Monitor operation: After cleaning, run the unit and observe if P3 still appears under normal load.
- Professional diagnostics: If P3 persists, a Vaillant technician should measure compressor current, check refrigerant pressures, and inspect the expansion device for restrictions.
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Repair Difficulty
Hard
4/5
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