Thermo King APU systems can experience various issues, often indicated by specific alarm codes on the HMI controller. Understanding these codes is crucial for effective troubleshooting and repair. This guide outlines the common Thermo King Apu Troubleshooting Codes: EnG, AcS, and ALt.
Common Thermo King APU Alarm Codes
EnG – Engine Failure
The “EnG” code signals a problem within the engine’s “8” circuit. This can stem from several issues:
- Open Engine Reset Switch: This is often triggered by low oil pressure or high water temperature, causing the system to shut down as a safety precaution.
- Main Power Off: Ensure the APU’s main power switch is in the “On” position. A simple oversight can trigger this code.
- Air in Coolant Lines: If the truck’s coolant was recently drained, air might be trapped in the APU’s coolant lines. Bleeding the system to remove air pockets can resolve this issue.
AcS – Air Conditioning System Failure
The “AcS” code points to a problem with the air conditioning system. Common causes include:
- High Discharge Pressure: This can indicate an overcharged system, blocked condenser, or faulty compressor.
- Low Pressure: This often suggests a refrigerant leak, requiring professional inspection and repair. Low refrigerant levels (needing Freon) is a common cause.
ALt – Alternator Failure
The “ALt” code indicates a charging system malfunction. This code typically appears if the alternator fails to produce output after two minutes of operation. Possible causes include:
- Faulty Alternator: The alternator itself might be defective and require replacement.
- Wiring Issues: Damaged or loose wiring in the charging circuit can prevent the alternator from functioning correctly.
- Voltage Regulator Problems: A malfunctioning voltage regulator can also lead to charging system issues.
Clearing Alarm Codes
To clear any of these alarm codes, turn off the TriPac system using the HMI Main Power Key. Addressing the underlying issue is crucial to prevent the code from reappearing.
These are the primary alarm codes for Thermo King TriPac APU systems. Consult your official Thermo King APU manual for comprehensive information and detailed troubleshooting procedures. Regular maintenance and prompt attention to these codes can help ensure the reliable operation of your Thermo King APU.
