What does Pr1 mean on an EVCO EV3 or EVK refrigeration controller?

Pr1 on the EVCO EV3 / EVK series indicates that probe Pb1 (the cabinet or room temperature probe) has failed open-circuit, short-circuit, or out-of-range. Regulation falls back to a duty-cycle compressor pattern based on parameter C4 while the probe is faulty. Disconnect the probe at the controller and measure resistance: a PTC probe should read approximately 990 Ω at 25 °C; an NTC 10 kΩ probe reads about 10 kΩ at 25 °C. Confirm parameter P0 matches the installed probe type (1 = PTC, 2 = NTC) before replacing the sensor.

What does AH (high temperature alarm) mean on an EVCO controller?

AH signals that the cabinet temperature has risen above the high-temperature alarm threshold (setpoint plus parameter A4) for longer than the configured delay. Refrigeration regulation continues; AH is a notification that resets automatically once temperature returns within the alarm band. Common causes are a fouled condenser, a stuck-open door, low refrigerant charge, or A4 set too narrow for the application. Inspect the condenser fan and coil first — dirty condensers are the most common driver — then verify door seals and product loading before adjusting parameter A4.

What does AL (low temperature alarm) mean on an EVCO EV3 or EVK controller?

AL flags that the cabinet temperature has dropped more than parameter A1 below setpoint for longer than the configured delay. Regulation is not interrupted — AL is a warning that resets automatically once temperature recovers. Frequent AL events usually mean A1 is too narrow for normal pull-down or defrost recovery, the door has been left open, defrost heaters are over-running, or the evaporator is iced over and reading erratically. Check the displayed temperature against an independent thermometer first to rule out a faulty probe.

What does COH mean on an EVCO refrigeration controller?

COH stands for Condenser Overheated and activates when the condenser probe reads above parameter C6. Regulation continues, but if the condenser temperature climbs further to C7 the controller escalates to CSd (Compressor Shut Down) and stops the compressor to protect it. The most common causes are a dirty condenser coil, a failed condenser fan or capacitor, blocked airflow clearances, and high ambient room temperature. Power down, brush the coil clean, verify all condenser fans spin freely, and confirm fan capacitors are within tolerance before adjusting C6.

What does AL01 mean on an EVCO C-PRO RACK or SAVE AHU controller?

AL01 has different meanings by family. On the C-PRO RACK refrigeration controller, AL01 is a compressor 1 thermal overload — the motor drew excess current and the overload contact opened. On the SAVE AHU controller, AL01 is a supply fan thermal overload that switches all AHU outputs off. Both alarms require the motor to cool 15–20 minutes before reset. Inspect the condenser or filters and dampers, test run capacitors, megger motor windings, and check fan belt condition before resetting; clearing the alarm without finding the root cause causes immediate re-trip.

What does AL09 / AL10 / AL12 / AL16 mean on an EVCO SAVE AHU controller?

On the EVCO SAVE AHU controller (144SAVEU0E01), AL09 and AL10 are signalling-only running-hour notifications for the supply and return fans — they prompt scheduled preventive maintenance and require a manual hour-counter reset. AL12 is a supply air temperature probe fault that inhibits the supply-temperature control loop until a valid NTC or PTC reading is restored. AL16 covers downstream-coil probe faults with the same fallback behaviour. None of the four shut the AHU down — but ignored running-hour alerts progress to AL01 thermal trips, and probe faults leave control loops disabled.

What does AL31 / AL41 / AL61 mean on an EVCO C-PRO RACK controller?

On the C-PRO RACK controller (144RACKNUE05), AL31 is a high discharge pressure alarm on circuit 1 that drives all condenser fans to full speed; AL41 is a low discharge pressure alarm that switches all circuit 1 fans OFF to let head pressure rebuild; AL61 is a liquid-level warning that the receiver level has dropped below the float-switch threshold and is often the first sign of a refrigerant leak. AL31 and AL41 self-reset; AL61 is visualisation-only but combined with bubbles in the sight glass or high superheat is a strong leak indicator.

What does PF (Power Failure) mean on an EVCO controller?

PF logs that the controller lost mains power and has since restored. Unlike temperature alarms, PF does not auto-reset — the operator must press any front-panel key to acknowledge and clear the display. The HACCP log records the timestamp of the outage. Recurrent PF events without a known grid outage usually indicate a loose terminal at the controller's L / N input, a building circuit-breaker pulling overload, or a supply voltage that drops below the controller's operating range. Verify supply voltage with a multimeter and tighten power-input terminals before assuming a grid issue.

What does F21 / F22 / F23 / F24 mean on an EVCO C-PRO RACK controller?

F21 through F24 are thermal overload alarms for individual condenser fans (1 through 4) on the C-PRO RACK controller. The motor's klixon or external overload relay has opened, and the controller switches that single fan OFF while leaving the rest running. Allow the motor to cool 15–20 minutes, manually rotate the fan blade to check for obstruction or seized bearings, test the run capacitor against its µF rating (replace if more than 10 % low), and megger the motor windings at 500 V before returning the fan to service. Repeated multi-fan trips usually point to a high-ambient or undersized-motor systemic issue.

What's the difference between EVCO EV3 / EVK, C-PRO RACK, SAVE AHU, and Vcolor controller fault codes?

EVCO sells controller families targeted at different equipment classes, and each uses a different code dictionary. EV3 / EVK series cabinet controllers (refrigerated cabinets, blast chillers, walk-ins) use Pr1–Pr3 for probe faults plus AH / AL / COH / PF / E1 / dF / Id. C-PRO RACK (multi-circuit refrigeration packs) uses AL01–AL77 plus F01–F24 fan series. SAVE AHU controllers use AL01–AL16 for fan, heater, damper and probe alarms. Vcolor and c-pro mega touch HMIs running OEM applications expose application-specific codes plus E01–E304 vector-drive faults. Confirm which controller family is installed before consulting any code table.

Quick Answer

EVCO controllers use family-specific code dictionaries. On EV3 / EVK refrigeration controllers, Pr1–Pr3 flag probe faults, AH and AL mark high and low temperature alarms, COH warns of condenser overheating, and PF logs power-failure events. On C-PRO RACK and SAVE AHU controllers, AL01–AL77 cover compressor and probe alarms, F21–F24 mark fan thermal trips, and E01–E304 indicate vector-drive faults.

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By Nichita Herput

Co-founder & CEO · Reviewed May 2026

What error codes does EVCO display?

Pr1

Probe Pb1 fault on EV3 / EVK — measure NTC / PTC resistance and replace probe

High-temperature alarm — inspect condenser cleanliness, fan operation and door seals

Low-temperature alarm — verify parameter A1 differential and rule out probe drift

COH

Condenser overheated warning — brush coil clean, test fan capacitors before C6 escalates to CSd

Power failure event — press any key to clear and tighten L / N input terminals if recurrent

AL01

Compressor 1 thermal overload (C-PRO RACK) or supply fan thermal overload (SAVE AHU) — cool 15–20 min before manual reset

AL31

High discharge pressure C1 on C-PRO RACK — controller drives all condenser fans to full speed

AL61

Liquid level alarm C1 on C-PRO RACK — visualisation-only warning, often first sign of a refrigerant leak

F21

Condenser fan 1 thermal overload on C-PRO RACK — cool motor, test capacitor and megger windings

AL12

Supply air temperature probe fault on SAVE AHU — inhibits supply-temperature control loop until probe restored

Common questions about EVCO equipment

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