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AL2Coreco

Coreco AL2

Carel RTN400 controller — LOW temperature alarm 2

Source: Coreco_rtn400_instruction_sheet_9is24288-1_rel0413_en_termostatos.pdf

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What does Coreco AL2 mean?

On the Coreco controller (Carel RTN400), AL2 is lOW temperature alarm 2: value read by probe 2 below LA2 after time set in tA2; label AL2 recorded in folder ALr; no effect on control.

Symptoms

  • Display/record shows AL2 in the ALr alarm folder
  • Cabinet colder than intended
  • No direct effect on control (alarm is signalled)

Common causes

  • Over-cooling
  • Alarm threshold/delay set too tight
  • Probe reading low

Diagnostic steps

  1. 01

    Confirm the low-temperature condition

    AL2 means the probe exceeded its LA threshold after the alarm delay. Note the temperature.

  2. 02

    Review thresholds and cooling

    Check LA/tA thresholds and whether the unit is over-cooling.

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When to call a professional

If the alarm reflects a genuine refrigeration fault, have a qualified refrigeration technician diagnose the sealed system; this work is reserved for qualified personnel.

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Other Coreco error codes

E0

Control probe (probe 1) error — signal interrupted, short-circuited or incompatible probe

E1

Evaporator / defrost probe (probe 2) error — signal interrupted, short-circuited or incompatible probe

E2

Condenser / product probe (probe 3) error — signal interrupted, short-circuited or incompatible probe

IA

Immediate or delayed alarm from the multifunction digital input (external alarm)

dOr

Open-door alarm from the door-switch digital input

LO

Low-temperature alarm — measured temperature below set point by more than parameter AL

HI

High-temperature alarm — measured temperature above set point by more than parameter AH

EE

Unit parameter reading (data) error — saved configuration data error

EF

Operating parameter reading (data) error — manual reset

Ed

Defrost ended by timeout — last defrost stopped on maximum duration, not on temperature

dF

Defrost running — status message shown during a defrost cycle (not an alarm)

CHt

Dirty-condenser warning/alarm — pre-alarm (cht) between Ac-AE and Ac, then alarm (CHt) when Ac is exceeded and refrigeration stops (manual reset)

View all Coreco error codes →