McQuay WMC Fault Code E10
McQuay WMC Fault Code E10 is a critical safety alarm indicating: Phase loss or reversal protection. The most common causes include One phase of power supply missing. 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 loss or reversal protection
Brand: McQuay | Model: WMC (Water-Cooled Screw Chiller) | Code: E10 | Severity: Critical
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
- One phase of power supply missing
- Phase sequence reversed
- Blown fuse on one phase
- Loose power connection
Recommended Inspection Steps
- Measure voltage on all three phases
- Check phase sequence with rotation tester
- Inspect and tighten all power connections
- Check and replace blown fuses
- Correct phase sequence at main disconnect
Required Tools & Equipment
- Digital multimeter
- Phase rotation tester
- Safety PPE (gloves, safety glasses, face shield)
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 McQuay service representative for warranty-covered repairs
Related Fault Codes
Other McQuay WMC codes that may be related:
OEM Service Manual Reference
OEM Reference: McQuay WMC Water-Cooled Screw Chiller Service Manual. Available through Daikin Applied (formerly McQuay) technical support.
Frequently Asked Questions
What does McQuay WMC fault code E10 mean?
Fault code E10 on a McQuay WMC chiller indicates: Phase loss or reversal protection. This is a critical safety alarm that requires diagnostic attention.
What causes McQuay WMC alarm code E10?
Common causes include: One phase of power supply missing; Phase sequence reversed; Blown fuse on one phase
How do I fix McQuay WMC error code E10?
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 McQuay service representative.