McQuay WMC Fault Code E04
McQuay WMC Fault Code E04 is a warning alarm indicating: Compressor discharge temperature high. The most common causes include Compression ratio too high from high head pressure. Estimated repair time: 2-4 hours (requires leak repair, evacuation, and refrigerant recharge). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Compressor discharge temperature high
Brand: McQuay | Model: WMC (Water-Cooled Screw Chiller) | Code: E04 | Severity: Warning
Observable Symptoms
- Discharge temperature gauge reads above 250F (121C)
- Discharge line may be hot enough to cause burns on contact
- Compressor oil may appear dark or burnt
What to Check First
Before diving into detailed diagnostics, start with this quick first check:
Probable Causes
- Compression ratio too high from high head pressure
- Compressor oil level low
- Condenser not rejecting heat adequately
Recommended Inspection Steps
- Check discharge pressure and temperature
- Verify oil level in compressor
- Inspect condenser water flow and temperature
- Check for non-condensables
- Verify refrigerant charge
Required Tools & Equipment
- Infrared thermometer or calibrated temperature probe
- Oil level sight glass inspection tool
- PT chart for refrigerant type
- Refrigerant manifold gauge set
- Safety PPE (gloves, safety glasses, face shield)
Estimated Repair Time
2-4 hours (requires leak repair, evacuation, and refrigerant recharge)
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 E04 mean?
Fault code E04 on a McQuay WMC chiller indicates: Compressor discharge temperature high. This is a warning alarm that requires diagnostic attention.
What causes McQuay WMC alarm code E04?
Common causes include: Compression ratio too high from high head pressure; Compressor oil level low; Condenser not rejecting heat adequately
How do I fix McQuay WMC error code E04?
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.