Trane RTAC Fault Code AB
Trane RTAC Fault Code AB is a warning alarm indicating: Evaporator Leaving Water Temperature Sensor. The most common causes include Sensor degradation. Estimated repair time: 30-60 minutes (requires sensor replacement and calibration verification). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Evaporator Leaving Water Temperature Sensor
Brand: Trane | Model: RTAC (Screw Compressor Chiller) | Code: AB | Severity: Warning
Observable Symptoms
- Temperature reading on controller display shows abnormal value or dashes
- Chiller may not start or cycles erratically due to incorrect temperature input
What to Check First
Before diving into detailed diagnostics, start with this quick first check:
Probable Causes
- Sensor degradation
- Wire damage from vibration
- Control board input failure
Recommended Inspection Steps
- Compare sensor reading to calibrated thermometer
- Inspect sensor wiring for damage
- Replace sensor if reading is incorrect
Required Tools & Equipment
- Infrared thermometer or calibrated temperature probe
- Safety PPE (gloves, safety glasses, face shield)
- Wire tracing and continuity tester
Estimated Repair Time
30-60 minutes (requires sensor replacement and calibration verification)
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 Trane service representative for warranty-covered repairs
Related Fault Codes
Other Trane RTAC codes that may be related:
OEM Service Manual Reference
OEM Reference: Trane RTAC Air-Cooled Rotary Screw Chiller Service Manual (SVR-SVN001-EN). Available through Trane Commercial support.
Frequently Asked Questions
What does Trane RTAC fault code AB mean?
Fault code AB on a Trane RTAC chiller indicates: Evaporator Leaving Water Temperature Sensor. This is a warning alarm that requires diagnostic attention.
What causes Trane RTAC alarm code AB?
Common causes include: Sensor degradation; Wire damage from vibration; Control board input failure
How do I fix Trane RTAC error code AB?
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 Trane service representative.