Lennox TCS Fault Code E24

E24
Hot gas bypass 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 TCS Fault Code E24 is a warning alarm indicating: Hot gas bypass fault. The most common causes include Hot gas bypass valve actuator failure. Estimated repair time: 1-2 hours. This alarm requires immediate attention by a certified HVAC technician.

Alarm Description

Hot gas bypass fault

Brand: Lennox  |  Model: TCS (Water-Cooled Screw Chiller)  |  Code: E24  |  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: Check valve actuator operation

Probable Causes

  • Hot gas bypass valve actuator failure
  • Valve position sensor fault
  • Control circuit damaged

Recommended Inspection Steps

  1. Check valve actuator operation
  2. Verify position sensor
  3. Inspect control wiring
  4. Replace actuator 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 TCS codes that may be related:

E01E02E03E04E05

OEM Service Manual Reference

OEM Reference: Lennox TCS Water-Cooled Screw Chiller Service Manual. Available through Lennox Commercial technical support.

Frequently Asked Questions

What does Lennox TCS fault code E24 mean?

Fault code E24 on a Lennox TCS chiller indicates: Hot gas bypass fault. This is a warning alarm that requires diagnostic attention.

What causes Lennox TCS alarm code E24?

Common causes include: Hot gas bypass valve actuator failure; Valve position sensor fault; Control circuit damaged

How do I fix Lennox TCS error code E24?

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 TCS service procedures.