Bitzer SE-E5

What does Bitzer SE-E5 mean?

The SE-E5 is a BITZER compressor protection device that monitors temperature, rotation direction, phase sequence and phase failure, suitable for frequency-inverter operation. Rotation is checked in the first 5 seconds after start; a wrong direction locks the device immediately. On phase failure between the 6th and 10th second it opens the safety chain and recloses after 6 minutes, but locks out after 3 phase failures within 18 minutes or 10 within 24 hours.

Symptoms

• Compressor stopped on over-temperature or a phase event
• Immediate lockout when starting in the wrong direction
• Safety chain reopens then recloses after about 6 minutes
• Permanent lockout after repeated phase failures

Common causes

• Winding, discharge-gas or oil temperature over the limit
• Wrong rotation direction detected at start
• Single or repeated phase failure on the supply
• Broken or shorted temperature-sensor cable

Diagnostic steps

1. 01

   Identify the fault type

   Distinguish a thermal trip from a rotation/phase fault; repeated phase failures (3 in 18 min or 10 in 24 h) cause a full lockout.

2. 02

   Confirm rotation direction

   Check phase sequence so the compressor starts in the correct direction within the first 5 seconds after start.

3. 03

   Investigate phase supply

   Look for a dropped phase if the safety chain opened between the 6th and 10th second after start and recloses after 6 minutes.

4. 04

   Address any thermal cause

   If temperature triggered the trip, allow cooldown and check the sensor cable for breaks or shorts.

5. 05

   Unlock the device

   After correcting the fault, interrupt the supply voltage for at least five seconds, then restore power to clear the lockout.

When to call a professional

Work on the compressor and system must be done by trained, authorized specialists. Diagnosing phase-rotation and phase-failure faults, and frequency-inverter wiring, involves live electrical work for a qualified technician. Repeated phase-failure lockouts or thermal trips signal a supply or motor problem that needs professional investigation rather than repeated manual unlocking.