Lennox SCA Fault Code E20
Lennox SCA Fault Code E20 is a warning alarm indicating: Compressor 2 motor protection. The most common causes include Internal motor protector tripped in compressor 2. Estimated repair time: 4-8 hours (requires refrigerant recovery, compressor changeout, evacuation, and recharge). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Compressor 2 motor protection
Brand: Lennox | Model: SCA (Air-Cooled Scroll Chiller) | Code: E20 | 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
- Internal motor protector tripped in compressor 2
- Motor winding insulation breakdown
- Bearing failure in compressor 2
Recommended Inspection Steps
- Allow compressor 2 to cool
- Measure motor winding resistance
- Inspect bearings
- Replace compressor if damaged
Required Tools & Equipment
- Digital multimeter
- Safety PPE (gloves, safety glasses, face shield)
Estimated Repair Time
4-8 hours (requires refrigerant recovery, compressor changeout, evacuation, and 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 Lennox service representative for warranty-covered repairs
Related Fault Codes
Other Lennox SCA codes that may be related:
OEM Service Manual Reference
OEM Reference: Lennox SCA Air-Cooled Scroll Chiller Service Manual. Available through Lennox Commercial technical support.
Frequently Asked Questions
What does Lennox SCA fault code E20 mean?
Fault code E20 on a Lennox SCA chiller indicates: Compressor 2 motor protection. This is a warning alarm that requires diagnostic attention.
What causes Lennox SCA alarm code E20?
Common causes include: Internal motor protector tripped in compressor 2; Motor winding insulation breakdown; Bearing failure in compressor 2
How do I fix Lennox SCA error code E20?
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 Lennox service representative.