McQuay WMC Fault Code E27
McQuay WMC Fault Code E27 is a warning alarm indicating: Condenser approach temperature high. The most common causes include Fouled condenser tubes. Estimated repair time: 4-6 hours (requires isolating water circuit, mechanical or chemical tube cleaning). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Condenser approach temperature high
Brand: McQuay | Model: WMC (Water-Cooled Screw Chiller) | Code: E27 | 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
- Fouled condenser tubes
- Non-condensables in system
- Refrigerant overcharge
- Condenser water flow too low
Recommended Inspection Steps
- Calculate condenser approach temperature
- Inspect condenser tubes for fouling
- Check for non-condensables
- Verify condenser water flow
- Clean condenser tubes
Required Tools & Equipment
- Coil cleaning brush and coil cleaner
- Infrared thermometer or calibrated temperature probe
- PT chart for refrigerant type
- Safety PPE (gloves, safety glasses, face shield)
Estimated Repair Time
4-6 hours (requires isolating water circuit, mechanical or chemical tube cleaning)
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 E27 mean?
Fault code E27 on a McQuay WMC chiller indicates: Condenser approach temperature high. This is a warning alarm that requires diagnostic attention.
What causes McQuay WMC alarm code E27?
Common causes include: Fouled condenser tubes; Non-condensables in system; Refrigerant overcharge
How do I fix McQuay WMC error code E27?
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.