Trane RTHD Fault Code 199B
Trane RTHD Fault Code 199B is a critical safety alarm indicating: Low Oil Flow - Compressor 2A. The most common causes include Oil filter clogged on circuit 2. Estimated repair time: 1-2 hours (requires oil addition or oil change, filter replacement). This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Low Oil Flow - Compressor 2A
Brand: Trane | Model: RTHD (Helical Rotary Chiller) | Code: 199B | Severity: Critical
Observable Symptoms
- Oil sight glass shows low level or empty
- Compressor may make unusual noise from lack of lubrication
- Oil pressure differential alarm may also be active
What to Check First
Before diving into detailed diagnostics, start with this quick first check:
Probable Causes
- Oil filter clogged on circuit 2
- Oil pump 2 failure
- Low oil level in compressor 2A
- Oil pressure switch 2 fault
Recommended Inspection Steps
- Check oil level in compressor 2A
- Replace oil filter on circuit 2
- Measure oil pump pressure on circuit 2
- Check oil pressure switch
Required Tools & Equipment
- Oil level sight glass inspection tool
- Safety PPE (gloves, safety glasses, face shield)
Estimated Repair Time
1-2 hours (requires oil addition or oil change, filter replacement)
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 199B mean?
Fault code 199B on a Trane RTHD chiller indicates: Low Oil Flow - Compressor 2A. This is a critical safety alarm that requires diagnostic attention.
What causes Trane RTHD alarm code 199B?
Common causes include: Oil filter clogged on circuit 2; Oil pump 2 failure; Low oil level in compressor 2A
How do I fix Trane RTHD error code 199B?
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.