Daikin EWAD Fault Code U3
Daikin EWAD Fault Code U3 is a warning alarm indicating: Transmission fault (main to inverter). The most common causes include Communication cable between main controller and inverter damaged. Estimated repair time: 1-3 hours (requires board replacement, configuration, and commissioning). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Transmission fault (main to inverter)
Brand: Daikin | Model: EWAD (Screw Compressor Chiller) | Code: U3 | Severity: Warning
Observable Symptoms
- Controller displays alarm code and description
- Chiller may be locked out or running in degraded mode
- Alarm indicator light is illuminated on control panel
What to Check First
Before diving into detailed diagnostics, start with this quick first check:
Probable Causes
- Communication cable between main controller and inverter damaged
- Inverter board power failure
- Protocol mismatch
Recommended Inspection Steps
- Check communication cable to inverter
- Verify inverter board power supply
- Check communication protocol
- Replace inverter communication board if faulty
Required Tools & Equipment
- Safety PPE (gloves, safety glasses, face shield)
- Wire tracing and continuity tester
Estimated Repair Time
1-3 hours (requires board replacement, configuration, and commissioning)
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 EWAD codes that may be related:
OEM Service Manual Reference
OEM Reference: Daikin EWAD Air-Cooled Screw Chiller Service Manual. Available through Daikin Applied technical support.
Frequently Asked Questions
What does Daikin EWAD fault code U3 mean?
Fault code U3 on a Daikin EWAD chiller indicates: Transmission fault (main to inverter). This is a warning alarm that requires diagnostic attention.
What causes Daikin EWAD alarm code U3?
Common causes include: Communication cable between main controller and inverter damaged; Inverter board power failure; Protocol mismatch
How do I fix Daikin EWAD error code U3?
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.