Applicable Systems
Octagon 4-Comp
Symptoms
The compressor reports a phase loss fault. One of the three supply phases is missing, preventing safe motor operation.
Possible Causes
- Blown fuse or tripped breaker on one phase
- Loose or corroded connection on one conductor
- Broken wire or damaged cable in the supply circuit
Troubleshooting Steps
- Step 1: Check voltage on all three phases at the compressor terminals
All three phase voltages are present and balanced - Step 2: Trace the missing phase back to the disconnect or breaker
Open fuse or loose connection is found and repaired - Step 3: Verify motor winding resistance is balanced across all phases
Resistance values are within 2 percent of each other
How to Reset
To reset: Restore all three phases, then reset the phase monitoring relay.
Source: Bitzer Screw Compressor Operating Instructions, Bitzer Kuhlmaschinenbau GmbH
Category: Refrigeration