Atlas Copco controller displays E022 Mains Failure Detection Fault
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.
Possible Causes
How to Fix / Troubleshooting
Safety first: Mains sensing circuits are connected to live utility voltage. Only qualified personnel should work on these circuits with appropriate lockout/tagout.
- Check sensing fuses: In the control panel, locate and test the small fuses protecting the mains sensing lines. Replace any blown fuses with the correct rating.
- Inspect wiring: Verify that the mains sensing wires are correctly connected to the ATS or mains terminals as per the Atlas Copco wiring diagram.
- Confirm configuration: In the controller settings, ensure the mains voltage and phase configuration (1‑phase/3‑phase, 230/400 V, etc.) match the actual supply.
- Measure mains at controller: With caution, measure voltage at the controller sensing terminals to confirm presence of mains. If present but not detected, the controller input may be faulty.
Persistent E022 alarms after wiring verification may require controller repair or replacement.
Repair Difficulty
Required Part
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