Lennox SCA Fault Code E26

E26
Cooling tower interlock fault
Warning
SAFETY WARNING: Commercial chillers contain high-pressure refrigerants and high-voltage electrical components (208V-4160V). Only EPA Section 608 certified technicians should perform diagnostic work. Always follow lockout/tagout procedures and wear appropriate PPE. Do not attempt repairs without proper training and equipment.
AI Summary

Lennox SCA Fault Code E26 is a warning alarm indicating: Cooling tower interlock fault. The most common causes include Cooling tower not running signal. Estimated repair time: 1-2 hours. This alarm requires immediate attention by a certified HVAC technician.

Alarm Description

Cooling tower interlock fault

Brand: Lennox  |  Model: SCA (Air-Cooled Scroll Chiller)  |  Code: E26  |  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:

Quick Start: Verify cooling tower is operating

Probable Causes

  • Cooling tower not running signal
  • Cooling tower interlock wiring damaged
  • Interlock relay fault

Recommended Inspection Steps

  1. Verify cooling tower is operating
  2. Check interlock wiring
  3. Test interlock relay
  4. Replace relay if faulty

Required Tools & Equipment

  • Safety PPE (gloves, safety glasses, face shield)
  • Wire tracing and continuity tester

Estimated Repair Time

1-2 hours

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:

E01E02E03E04E05

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 E26 mean?

Fault code E26 on a Lennox SCA chiller indicates: Cooling tower interlock fault. This is a warning alarm that requires diagnostic attention.

What causes Lennox SCA alarm code E26?

Common causes include: Cooling tower not running signal; Cooling tower interlock wiring damaged; Interlock relay fault

How do I fix Lennox SCA error code E26?

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.

Disclaimer: All lookup data is for reference only. Do not use this information to replace certified professional HVAC technician judgment. Always refer to original OEM official service manual for Lennox SCA service procedures.