Randell E01

What does Randell E01 mean?

On a Randell prep table with the Danfoss controller, E01 is the S1 Sensor Failure alarm. S1 is one of the controller's temperature sensors (thermistors) used to monitor the cabinet or coil. E01 indicates the controller cannot get a valid reading from S1 because the sensor has failed, gone out of range, or lost its connection.

Symptoms

• Display shows E01 with the alarm LED lit
• Temperature regulation tied to the S1 sensor is affected
• Displayed temperature may be missing or incorrect
• Compressor may not cycle normally

Common causes

• Failed or out-of-range S1 thermistor
• Disconnected or loose S1 sensor connector at the controller
• Damaged sensor wiring
• Controller input fault

Diagnostic steps

1. 01

   Confirm the alarm

   Verify the Danfoss display reads E01, the S1 Sensor Failure alarm.

2. 02

   Disconnect power before inspecting

   Ensure the unit is disconnected from its power source before checking the sensor or wiring, per the manual.

3. 03

   Inspect the S1 sensor connection

   Check that the S1 thermistor is connected at the controller and that its wiring is not damaged or loose.

4. 04

   Verify cabinet temperature

   Compare the displayed temperature against the set point to judge whether the unit is still holding safe temperature.

5. 05

   Contact service

   The Danfoss table directs contacting service for a sensor failure; call 888-994-7636 to test or replace the S1 thermistor.

When to call a professional

The Danfoss code table directs contacting service for an S1 sensor failure. Sensor diagnosis and replacement with the correct OEM thermistor should be handled by a Randell Authorized Service Agent, since the manual requires factory-authorized service with OEM parts on these R290 units to avoid ignition risk. Call service at 888-994-7636 if E01 does not clear after checking the connection.