Randell LO

What does Randell LO mean?

On a Randell prep table, the low-temperature alarm shows as LO on the Carel controller and Lo on the Danfoss controller. It means the cabinet temperature has dropped below the controller's low-temperature alarm threshold, so the unit is running colder than intended for the rail or base it is monitoring.

Symptoms

• Display shows LO (Carel) or Lo (Danfoss) with the alarm LED lit
• Cabinet or product is colder than the desired set point
• Product near the coil may begin to freeze
• Compressor runs more than expected

Common causes

• Set point adjusted too low (incorrect set point)
• Control probe reading low or out of position
• Controller running the compressor beyond the target temperature
• Sensor fault feeding a low reading to the controller

Diagnostic steps

1. 01

   Confirm the low alarm

   Verify the display reads LO (Carel) or Lo (Danfoss) with the alarm LED lit.

2. 02

   Check and adjust the set point

   The manual lists an incorrect set point as a cause of a unit running too cold; adjust the control set point, changing it in small increments.

3. 03

   Make changes gradually

   Per the manual, make set-point changes in 2-degree increments and allow the unit to operate 24 hours between adjustments.

4. 04

   Verify the probe position

   Confirm the control probe is in place and reading correctly, since a misreading probe can drive a low alarm.

5. 05

   Contact service if needed

   The Danfoss table directs you to contact service for the low-temperature alarm if it does not clear; call 888-994-7636.

When to call a professional

A low-temperature alarm caused by an over-cold set point is owner-adjustable. Call a Randell Authorized Service Agent when the alarm persists after correcting the set point, when product is freezing, or when a probe or controller fault is suspected. The Danfoss code table itself directs contacting service for this alarm. All controller and refrigeration service on these R290 units must be factory-authorized; reach service at 888-994-7636.