Dixell/Copeland E01

What does Dixell/Copeland E01 mean?

On the Dixell XEV02D digital compressor PWM valve driver, E01 indicates an active DLT (Discharge Line Temperature) alarm. The DLT probe P2 has measured a temperature at or above the dLt setpoint. The module disables its output and activates the alarm relay. The fault resets automatically once P2 drops below dLt minus the dth differential and the compressor head-cooling standby timer (dCt) expires.

Symptoms

• Display shows 'E01'; output TRIAC and compressor relay are disabled.
• Alarm relay and open-collector output activate.
• Buzzer sounds (if enabled via bEn parameter).
• Regulation restarts automatically after temperature drops below reset threshold and dCt timer expires.

Common causes

• Discharge line temperature exceeding the dLt setpoint — most commonly from insufficient refrigerant charge.
• Condenser coil fouled or airflow restricted, causing high condensing temperature.
• DLT probe P2 incorrectly positioned or not making proper thermal contact with the discharge line.
• Faulty or out-of-calibration DLT probe reading higher than actual temperature.
• System operating outside design load conditions, driving discharge temperature above limits.

Diagnostic steps

1. 01

   Verify DLT probe placement and contact

   Confirm that probe P2 is properly clamped to the discharge line, at the recommended location per system design. Poor contact causes false high readings.

2. 02

   Check refrigerant charge

   Connect manifold gauges. Low refrigerant charge is the leading cause of elevated discharge temperatures. Compare suction and discharge pressures to design values for the operating conditions.

3. 03

   Inspect condenser coil and airflow

   Clean condenser coil if dirty. Confirm condenser fan(s) are operating and that no airflow recirculation is occurring. Elevated condensing temperature directly raises discharge temperature.

4. 04

   Check dLt parameter setting

   Verify the dLt setpoint in the XEV02D parameter menu is appropriate for the application refrigerant. An incorrectly low setpoint generates nuisance trips.

5. 05

   Allow automatic reset

   Once root cause is corrected, the E01 alarm resets automatically when temperature falls below (dLt − dth) and the dCt head-cooling timer expires. No manual reset is required for single-event DLT trips.

When to call a professional

If discharge temperatures remain elevated after verifying condenser operation, or if a refrigerant charge issue is identified, a licensed refrigeration technician is required for refrigerant system service. Repeated E01 events that escalate to E02 lockout require manual controller reset and an investigation into system-level overload conditions.