Coreco LoP Error Code
Carel RTN400 controller — LOW voltage alarm
Source: Coreco_rtn400_instruction_sheet_9is24288-1_rel0413_en_termostatos.pdf
What does Coreco LoP mean?
On the Coreco controller (Carel RTN400), LoP is lOW voltage alarm: voltage value read by the analog input is lower than the SPL value; display label LoP, alarm icon permanently on; regulation locked depending on SoU value.
Symptoms
- Display shows LoP
- Alarm icon permanently on
- Regulation may lock depending on the SoU setting
Common causes
- Supply/analog-input voltage outside the SPH/SPL limits
- Unstable mains supply
- Wiring or sensor issue on the analog input
Ask the AskWhiz AI about Coreco LoP
AskWhiz
online
Diagnostic steps
Check the supply voltage
LoP means the measured voltage is outside the configured SPH/SPL limits. Verify the actual supply against the limits.
When to call a professional
Electrical supply diagnosis is reserved for qualified personnel.
Stop searching through PDFs. Our AI assistant on WhatsApp is trained on official Coreco documentation and can diagnose this fault code and guide you through the repair in minutes.
5 free questions per bot in your browser — no signup.
Other Coreco Error Codes
Control probe (probe 1) error — signal interrupted, short-circuited or incompatible probe
Evaporator / defrost probe (probe 2) error — signal interrupted, short-circuited or incompatible probe
Condenser / product probe (probe 3) error — signal interrupted, short-circuited or incompatible probe
Immediate or delayed alarm from the multifunction digital input (external alarm)
Open-door alarm from the door-switch digital input
Low-temperature alarm — measured temperature below set point by more than parameter AL
High-temperature alarm — measured temperature above set point by more than parameter AH
Unit parameter reading (data) error — saved configuration data error
Operating parameter reading (data) error — manual reset
Defrost ended by timeout — last defrost stopped on maximum duration, not on temperature
Defrost running — status message shown during a defrost cycle (not an alarm)
Dirty-condenser warning/alarm — pre-alarm (cht) between Ac-AE and Ac, then alarm (CHt) when Ac is exceeded and refrigeration stops (manual reset)
AskWhiz Playground
Test your diagnostic skills
Play a real HVAC service call in the AskWhiz Playground — real brands, real fault codes, no signup.
Play a real service call