Lennox TCS Fault Code E19

E19
Compressor 2 low pressure
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 E19 is a warning alarm indicating: Compressor 2 low pressure. The most common causes include Low refrigerant on circuit 2. Estimated repair time: 45-90 minutes. This alarm requires immediate attention by a certified HVAC technician.

Alarm Description

Compressor 2 low pressure

Brand: Lennox  |  Model: TCS (Water-Cooled Screw Chiller)  |  Code: E19  |  Severity: Warning

Observable Symptoms

  • Suction pressure gauge reads below normal operating range
  • Compressor may short cycle or run continuously without cooling
  • Frost may appear on suction line or evaporator

What to Check First

Before diving into detailed diagnostics, start with this quick first check:

Quick Start: Check charge on circuit 2

Probable Causes

  • Low refrigerant on circuit 2
  • Expansion valve 2 issue
  • Evaporator flow on circuit 2 low

Recommended Inspection Steps

  1. Check charge on circuit 2
  2. Inspect expansion valve 2
  3. Measure water flow on circuit 2

Required Tools & Equipment

  • PT chart for refrigerant type
  • Safety PPE (gloves, safety glasses, face shield)

Estimated Repair Time

45-90 minutes

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 E19 mean?

Fault code E19 on a Lennox TCS chiller indicates: Compressor 2 low pressure. This is a warning alarm that requires diagnostic attention.

What causes Lennox TCS alarm code E19?

Common causes include: Low refrigerant on circuit 2; Expansion valve 2 issue; Evaporator flow on circuit 2 low

How do I fix Lennox TCS error code E19?

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.