Traulsen Discharge Line Sensor Open or Shorted

What does Traulsen Discharge Line Sensor Open or Shorted mean?

This alarm means the controller cannot read a valid signal from the discharge line sensor because its circuit is open or shorted. The discharge sensor monitors hot-gas temperature near the compressor and feeds the system leak detection logic, so a faulty probe can both trigger this alarm and interfere with leak detection. A correct sensor reads about 32.7K ohms at 32F within ten percent.

Symptoms

• Alarm LED illuminated and horn sounding on the control
• Discharge temperature reading missing or implausible
• System leak detection behaving unexpectedly
• Sensor resistance out of the expected range when tested

Common causes

• Discharge line sensor probe disconnected or loosely connected
• Open circuit in the discharge sensor wiring
• Shorted discharge line sensor
• Dislocated or uninsulated probe, or a failed sensor outside the 32.7K ohm range at 32F

Diagnostic steps

1. 01

   Locate the discharge sensor

   Access the discharge sensor mounted on the hot-gas side of the compressor (R and A Series).

2. 02

   Check the connection

   Confirm the discharge probe is properly connected and reconnect it if loose.

3. 03

   Test sensor resistance

   Disconnect the sensor and place the probe in ice water; at 32F resistance should read about 32.7K ohms plus or minus ten percent.

4. 04

   Verify placement and insulation

   Ensure the probe sits close to the compressor before the hot-gas loop and is insulated as required.

5. 05

   Replace a failed sensor

   If resistance is out of range or the probe is damaged, replace the discharge line sensor.

When to call a professional

Call a technician if reconnecting and re-placing the probe does not clear the alarm. The discharge sensor must be positioned near the compressor before the hot-gas loop and insulated; getting this wrong skews leak detection. Testing the probe against the 32.7K-ohm spec and replacing it are service tasks that should be done by qualified personnel.