McQuay ALS Fault Code E01
McQuay ALS Fault Code E01 is a critical safety alarm indicating: Compressor high pressure protection. The most common causes include Condenser coil fouled. 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
Compressor high pressure protection
Brand: McQuay | Model: ALS (Air-Cooled Screw Chiller) | Code: E01 | Severity: Critical
Observable Symptoms
- Compressor shuts down on high pressure safety cutout
- Discharge pressure gauge reads above normal operating range
- Condenser may feel hot to touch or airflow feels restricted
What to Check First
Before diving into detailed diagnostics, start with this quick first check:
Probable Causes
- Condenser coil fouled
- Condenser fan failure
- Non-condensables
- Refrigerant overcharge
Recommended Inspection Steps
- Clean condenser coils
- Verify fan operation
- Check non-condensables
- Verify charge
Required Tools & Equipment
- Coil cleaning brush and coil cleaner
- Oil level sight glass inspection tool
- 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 ALS codes that may be related:
OEM Service Manual Reference
OEM Reference: McQuay ALS Air-Cooled Screw Chiller Service Manual. Available through Daikin Applied technical support.
Frequently Asked Questions
What does McQuay ALS fault code E01 mean?
Fault code E01 on a McQuay ALS chiller indicates: Compressor high pressure protection. This is a critical safety alarm that requires diagnostic attention.
What causes McQuay ALS alarm code E01?
Common causes include: Condenser coil fouled; Condenser fan failure; Non-condensables
How do I fix McQuay ALS error code E01?
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.