Trane RTHD Fault Code 397
Trane RTHD Fault Code 397 is a warning alarm indicating: Frozen Condenser Water Sensor. The most common causes include Condenser water temperature sensor reading below freezing. Estimated repair time: 30-60 minutes (requires sensor replacement and calibration verification). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Frozen Condenser Water Sensor
Brand: Trane | Model: RTHD (Helical Rotary Chiller) | Code: 397 | 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
- Condenser water temperature sensor reading below freezing
- Sensor fault or miscalibration
- Actual condenser water near freezing
Recommended Inspection Steps
- Verify actual condenser water temperature
- Check sensor resistance vs temperature chart
- Replace sensor if reading is incorrect
- Implement freeze protection if water is actually near freezing
Required Tools & Equipment
- Digital multimeter
- Infrared thermometer or calibrated temperature probe
- Safety PPE (gloves, safety glasses, face shield)
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 RTHD codes that may be related:
OEM Service Manual Reference
OEM Reference: Trane RTHD Water-Cooled Helical Rotary Chiller Service Manual (SVR-SVN002-EN). Trane CH530 Controls manual also required.
Frequently Asked Questions
What does Trane RTHD fault code 397 mean?
Fault code 397 on a Trane RTHD chiller indicates: Frozen Condenser Water Sensor. This is a warning alarm that requires diagnostic attention.
What causes Trane RTHD alarm code 397?
Common causes include: Condenser water temperature sensor reading below freezing; Sensor fault or miscalibration; Actual condenser water near freezing
How do I fix Trane RTHD error code 397?
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.