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Coreco nPA

Carel RTN400 controller — General pressure switch alarm (n < PEn, Auto Reset)

Source: Coreco_rtn400_instruction_sheet_9is24288-1_rel0413_en_termostatos.pdf

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What does Coreco nPA mean?

On the Coreco controller (Carel RTN400), nPA is general pressure switch alarm (n < PEn, Auto Reset): activation of pressure switch alarm by general pressure switch; folder nPA recorded in folder ALr; regulation blocked.

Symptoms

  • Display/record shows nPA
  • Regulation blocked while the alarm is active
  • Pressure-switch input tripped

Common causes

  • Refrigeration pressure outside limits (high or low)
  • Dirty condenser / restricted airflow (high pressure)
  • Low refrigerant charge or restriction (low pressure)
  • Faulty pressure switch or wiring

Diagnostic steps

  1. 01

    Identify the pressure fault

    nPA is a pressure-switch alarm. Determine whether it is high or low pressure and whether reset is automatic or manual.

  2. 02

    Investigate the refrigeration cause

    Check the condenser/airflow for high-pressure trips or charge/restriction for low-pressure trips.

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When to call a professional

Pressure faults involve the sealed refrigeration system and must be diagnosed by a qualified refrigeration technician.

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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 →