Carel ir33 (refrigeration)

Panel controller for cabinets and cool rooms with up to five probes, compressor, defrost, evaporator fan, alarm and aux relays, HACCP logging and an optional real-time clock.

What it is: Refrigeration controller. Same menu logic on ir33 power, ir33 DIN, powercompact and MasterCella. The models differ in which parameters are visible.

Key combo: Frequent (F) parameters: hold PRG for 5 s. Configuration (C) parameters: hold PRG + SET for 5 s, enter the service password, press SET.

Error codes ↓
Enter service mode ↓
Parameters ↓
Change a setting ↓

Carel ir33 (refrigeration) error codes

Code	Meaning	Likely cause	How to reset
rE	Virtual control probe fault	The probe (or probe mix) used for control has failed	Clears by itself once the probe reads again. The compressor runs on the duty setting (c4).
E0	Room probe (S1) fault	Probe open or shorted, wrong probe type, wiring	Clears by itself when the probe reads normally.
E1	Defrost probe (S2) fault	Probe open or shorted, wiring	Clears by itself. Defrost then ends on time.
E2 / E3 / E4	Probe S3 / S4 / S5 fault	Probe open or shorted, or a probe enabled that is not fitted	Clears by itself. Check the /A2–/A4 probe settings.
LO	Low temperature alarm	Temperature below the AL limit for longer than Ad	Clears by itself when temperature recovers.
HI	High temperature alarm	Temperature above the AH limit for longer than Ad	Clears by itself when temperature recovers.
AFr	Antifreeze alarm	Temperature below the ALF set point for longer than AdF	Manual reset: hold PRG + UP for 5 s once the cause is gone.
IA	Immediate external alarm	Digital input set as an immediate alarm has opened	Clears when the contact closes.
dA	Delayed external alarm	Digital input open for longer than A7	Clears when the contact closes.
Ed1 / Ed2	Defrost on evaporator 1 / 2 ended on time, not temperature	Defrost heater, probe position, ice load, dt1 / dP1 too low	Shown only if A8 = 1. Clears on the next defrost that ends on temperature, or by manual reset.
Pd	Maximum pump-down time exceeded	Pump-down did not finish within c7	Automatic or manual depending on settings.
LP	Low pressure alarm	Low-pressure switch input open	Automatic or manual depending on settings. Compressor stops.
AtS	Auto-start in pump-down	Compressor restarted itself during pump-down	Automatic or manual depending on settings.
cht	High condenser temperature pre-alarm	Condenser above Ac – dirty coil, fan fault	Clears by itself once the condenser cools.
CHt	High condenser temperature alarm	Condenser stayed above Ac + AE for Acd	Manual reset: hold PRG + UP for 5 s. Compressor stops.
dor	Door open too long	Door switch open past the set delay	Clears when the door closes.
Etc	Real-time clock fault	Clock not set or clock failure	Set the clock (tc parameters).
EE	Unit parameter memory error	Corrupt EEPROM data	Clears by itself if the error goes away. If it stays, the controller needs replacing.
EF	Operating parameter memory error	Corrupt parameters, failed default set load	Re-check and re-save the parameters. Power cycle restores the previous set after a failed load.
HA / HF	HACCP high-temperature / power-failure event logged	Logged temperature event or blackout	Manual: in the HACCP menu, clear with UP + SET as described below.

How to enter service / parameter mode

F parameters (frequent use): hold PRG for more than 5 seconds. If an alarm is active, the first press mutes the buzzer. The first F parameter appears.
C parameters (configuration): hold PRG and SET together for more than 5 seconds. 00 appears (password prompt).
Enter the service password with UP or DOWN, then press SET. The first C parameter appears.
Press PRG at any time to jump to the category list (Pro, CtL, CMP, dEF, ALM, Fan, CnF, HcP, rtc), pick one and press SET to jump to its first parameter.

Parameter list

Code	What it does	Range	Default / typical
St	Set point	r1 to r2	0.0
rd	Control differential	0.1–20	2.0
r1 / r2	Minimum / maximum set point allowed	r1 −50 to r2; r2 r1 to 200	−50 / 60
r3	Operating mode: 0 cooling with defrost, 1 cooling only, 2 heating	0–2	0
r4	Set point change from the digital input (night mode)	−20 to 20	3.0
/c1	Probe 1 calibration offset	−20 to 20	0.0
/A2	Probe 2 use (for example 2 = evaporator, 3 = condenser)	0–4	2
c0	Compressor and fan start delay at power-up	0–15 min	0
c1 / c2 / c3	Minimum time between starts / minimum off time / minimum on time	0–15 min	0
c4	Duty setting (compressor run time while the control probe has failed)	0–100 min	0
cc	Continuous cycle length	0–15 h	0
d0	Defrost type: 0 electric/temperature, 1 hot gas/temperature, 2 electric/time, 3 hot gas/time	0–4	0
dI	Interval between defrosts	0–250 h	8
dt1	Defrost end temperature (evaporator 1)	−50 to 200	4.0
dP1	Maximum defrost time (evaporator 1)	1–250 min	30
d4 / d5	Defrost at power-up / delay before that defrost	0–1; 0–250 min	0 / 0
d6	Display during defrost: 0 dF flashing, 1 frozen reading, 2 dEF	0–2	1
dd	Drip time after defrost	0–15 min	2
d8	Temperature alarms ignored after defrost	0–15 h	1
A0	Alarm and fan differential	0.1–20	2.0
A1	AL / AH are relative to set point (0) or absolute (1)	0–1	0
AL / AH	Low / high temperature alarm limit	−50 to 200	0.0 / 0.0
Ad	Temperature alarm delay	0–250 min	120
A4 / A5	Digital input 1 / 2 function	0–15	0
A8	Enable Ed1 / Ed2 (defrost ended on time) warnings	0–1	0
Ac / AE / Acd	Condenser high temperature alarm: set point / differential / delay	0–200; 0.1–20; 0–250 min	70.0 / 10.0 / 0
F0	Evaporator fan control mode (0 by F2/F3/Fd, 1 room–evap difference, 2 evap temperature)	0–2	0
F1	Fan start temperature	−50 to 200	5.0
F2	Fans stop when the compressor stops (1 = yes)	0–1	1
F3	Fans off during defrost (1 = off)	0–1	1
Fd	Fan delay after drip time	0–15 min	1
H1	Relay 4 function (alarm, aux, light…)	0–11	1
H2	Keypad and remote control lock	1–6	1
H4	Buzzer disable (1 = off)	0–1	0

How to change and save a setting

Scroll to the parameter with UP or DOWN.
Press SET to show the value.
Change it with UP or DOWN.
Press SET to keep it for now and go back to the code.
When finished, hold PRG for more than 5 seconds to save everything to memory and exit.
If you wait 60 seconds without a key, or switch off before saving, all changes are thrown away (clock settings are kept).

Other useful key presses

Task	How
Reset manual-reset alarms	Hold PRG + UP for more than 5 s once the cause has been fixed.
Restore defaults (Hdn = 0)	Power off, then power on holding PRG until _Std_ shows. Only visible parameters are reset.
Set point	Hold SET for 1 s, adjust with UP/DOWN, press SET to confirm.
HACCP log	Open the HACCP menu, pick HA or HF and scroll the date, time and duration of the last event.

Notes

Ranges and defaults are from the v1.131 summary sheet and vary by model and firmware. Many parameters are hidden on some models.
Units for temperature parameters follow /5 (°C or °F).

For licensed technicians only. This equipment can involve mains voltage, high-voltage microwave circuits, gas and refrigerant. Isolate power (and gas) before opening panels, follow the manufacturer's manual and your local licensing rules (for example ARC refrigerant handling and electrical or gas licences). Wrong settings can spoil food or damage equipment. Check every value on the unit in front of you before changing it.

Based on: Carel ir33 platform user manual (+030220441 rel. 2.5) and the ir33 v1.131 parameter summary. Always check the manual for your exact model and software version.

ServiceModes is not affiliated with Carel or any other manufacturer. Written in our own words from the manufacturer's documentation.