Traulsen Liquid Line Sensor Open or Shorted

What does Traulsen Liquid Line Sensor Open or Shorted mean?

This alarm means the controller cannot read a valid signal from the liquid line sensor because its circuit is open or shorted. The liquid line temperature is monitored on Smart Control units and contributes to liquid-line and shutdown alarm logic, so an invalid reading must be corrected for the control to protect the system properly.

Symptoms

• Alarm LED illuminated and horn sounding on the control
• Liquid line temperature reading missing or implausible
• Liquid line or shutdown alarm status behaving unexpectedly
• Sensor resistance out of the expected range when tested

Common causes

• Liquid line sensor probe disconnected or loosely connected
• Open circuit in the liquid line sensor wiring
• Shorted liquid line sensor
• Failed liquid line sensor reading outside the expected range

Diagnostic steps

1. 01

   Locate the liquid line sensor

   Access the liquid line sensor on the refrigeration circuit per the unit's service documentation.

2. 02

   Check the connection

   Confirm the liquid line probe is properly connected and reconnect it if loose or disconnected.

3. 03

   Test sensor resistance

   Disconnect the sensor and verify resistance against the Intela-Traul sensor spec of about 32.7K ohms at 32F plus or minus ten percent.

4. 04

   Replace a failed sensor

   If resistance is outside the expected range, replace the liquid line sensor.

5. 05

   Confirm alarm clears

   After reconnection or replacement, verify the liquid line alarm status returns to normal on the control.

When to call a professional

Call a technician if reconnecting the probe does not clear the alarm or if you cannot meter the sensor against spec. The liquid line sensor feeds liquid-line and shutdown alarm logic, so a wrong reading can mask a real sealed-system problem. Testing and replacing refrigeration-circuit sensors are service tasks best handled by qualified personnel.