Dixell/Copeland E12

What does Dixell/Copeland E12 mean?

The XWi70K controller reports E12 when Embraco variable-speed compressor 1 (EMB1) has fallen below its minimum operating speed threshold. Regulation is stopped and the built-in retry function activates automatically. The same fault on compressor 2 is displayed as E22. This is a serial-bus fault reported directly from the Embraco inverter module over the CAB/EMB serial cable.

Symptoms

• Controller display shows 'E12' or 'E22' for compressor 1 or 2 respectively.
• Compressor output relay de-energizes; cooling regulation stops.
• Alarm output activates and buzzer sounds.
• Retry function cycles the compressor; unit attempts automatic restart.

Common causes

• Low supply voltage causing the inverter to lose speed control.
• Refrigerant charge too low, reducing compressor load and causing speed drop.
• Mechanical restriction in the compressor (seized bearings or locked rotor at low speed).
• Faulty or damaged CAB/EMB serial cable between controller and Embraco inverter.
• Inverter module failure — internal drive fault flagging under-speed to the XWi70K.

Diagnostic steps

1. 01

   Check supply voltage

   Measure AC supply at the unit terminals. Voltage must be within ±10% of rated value. Low voltage is the leading cause of inverter under-speed trips.

2. 02

   Inspect the CAB/EMB serial cable

   Verify cable DD190001 51 (for Embraco models) is fully seated at both the XWi70K serial port and the compressor inverter port. Reseat connectors and inspect for damage or corrosion.

3. 03

   Check refrigerant charge

   Connect manifold gauges and compare suction and discharge pressures to manufacturer spec. An undercharged system reduces motor load and can cause the inverter to detect under-speed.

4. 04

   Allow automatic retry

   The XWi70K retry function will attempt to restart the compressor automatically. Monitor the number of retry attempts; if faults repeat continuously, proceed with further diagnostics.

5. 05

   Inspect Embraco inverter module

   Check the inverter module for fault LEDs or diagnostic codes per the Embraco inverter product manual. A hardware fault in the module requires inverter replacement.

When to call a professional

Call a licensed refrigeration technician if the fault recurs after multiple automatic retries, if supply voltage checks out, or if the refrigerant system requires service. Inverter module replacement and refrigerant system work require certified technicians. Repeated under-speed faults that are not cleared by retry indicate a hardware problem beyond field-level reset.