Randell E1
Defrost probe alarm on the Carel controller (evaporator/defrost temperature sensor)
Source: Randell/8148n-290-pcb__rd-8000-290-9000w-290-spm.pdf
What does Randell E1 mean?
On a Randell prep table with the Carel controller, E1 is the defrost-probe alarm. The defrost probe is the sensor that monitors the evaporator coil to manage the defrost cycle. E1 indicates this probe has failed, drifted out of range, or lost connection, so the controller cannot reliably read coil temperature to start and end defrosts.
Symptoms
- Display shows E1 with the alarm LED lit
- Defrost cycles do not run or do not end correctly
- Frost or ice builds up on the evaporator
- Cabinet may struggle to hold its set point
Common causes
- Failed or out-of-range defrost (evaporator) probe
- Loose or disconnected probe connector at the controller
- Damaged probe wiring near the evaporator
- Controller input fault
Diagnostic steps
- 01
Confirm the alarm code
Verify the Carel display reads E1 with the alarm LED lit, identifying it as the defrost-probe alarm.
- 02
Disconnect power first
Ensure the unit is disconnected from its power source before inspecting the probe or wiring, per the manual.
- 03
Inspect the defrost probe and its routing
Check the probe connection at the controller and the wiring run to the evaporator for damage or a loose connector.
- 04
Check for ice buildup
Look at the evaporator for excessive frost, which can indicate defrosts are not completing while the probe alarm is active.
- 05
Contact authorized service
If the defrost probe is faulty, contact a Randell Authorized Service Agent at 888-994-7636 to test or replace it.
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When to call a professional
Diagnosing and replacing the defrost probe inside the cabinet, and clearing related ice buildup, is service-technician work on these R290 units. Randell requires factory-authorized service with OEM parts to keep the flammable-refrigerant system safe. If E1 remains after checking the probe connection, or frost keeps building on the coil, call service at 888-994-7636.
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