Daikin WME Fault Code U1
Daikin WME Fault Code U1 is a warning alarm indicating: Phase sequence error. The most common causes include Phase sequence reversed. Estimated repair time: 30-60 minutes (requires electrical power diagnostics at disconnect). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Phase sequence error
Brand: Daikin | Model: WME (Water-Cooled Screw Chiller) | Code: U1 | Severity: Warning
Observable Symptoms
- Phase monitor relay indicates phase loss or reversal
- Compressor may run backwards or fail to start
- Three-phase voltage readings are unbalanced
What to Check First
Before diving into detailed diagnostics, start with this quick first check:
Probable Causes
- Phase sequence reversed
- Phase loss
- Wiring error
Recommended Inspection Steps
- Check phase sequence
- Verify all phases
- Correct sequence
- Check fuses
Required Tools & Equipment
- Phase rotation tester
- Safety PPE (gloves, safety glasses, face shield)
- Wire tracing and continuity tester
Estimated Repair Time
30-60 minutes (requires electrical power diagnostics at disconnect)
When to Call a Professional
- If the fault persists after completing all recommended inspection steps
- If you observe unusual noises, vibrations, or oil leaks from the compressor
- If refrigerant charge levels are outside OEM specifications and EPA-certified recovery is needed
- If electrical measurements show voltage imbalance greater than 2% between phases
- If the fault recurs immediately after reset, indicating an unresolved safety condition
- Contact an authorized Daikin service representative for warranty-covered repairs
Related Fault Codes
Other Daikin WME codes that may be related:
OEM Service Manual Reference
OEM Reference: Daikin WME Water-Cooled Screw Chiller Service Manual. Available through Daikin Applied technical support.
Frequently Asked Questions
What does Daikin WME fault code U1 mean?
Fault code U1 on a Daikin WME chiller indicates: Phase sequence error. This is a warning alarm that requires diagnostic attention.
What causes Daikin WME alarm code U1?
Common causes include: Phase sequence reversed; Phase loss; Wiring error
How do I fix Daikin WME error code U1?
Follow the recommended inspection steps below. Start with the quick check, then proceed through each step. If the fault persists after all steps, contact an authorized Daikin service representative.