The Carel IR33 is one of the most common controllers on coolrooms, display fridges and freezers. It is also easy to get lost in: a small display, a handful of keys, and a long list of parameter codes. This guide covers what most people actually need: how to enter the Carel controller password, which Carel controller parameters matter, how to set the temperature, start a defrost, reset the unit and read E0 and E1.
The facts below come from Carel's own IR33+ manual, plus programming sheets published by Zero Zone and Hawco, and we link to them so you can check any step. We don't sell Carel controllers, so there is no sales pitch here. The related parts we do stock are listed near the end.
Quick answer: the Carel IR33 configuration password is 22. Hold the Prg key until the display shows 0 (PS), scroll to 22 with UP, press SET, change the parameter, then hold Prg for about 5 seconds to save. If you cut the power before saving, the change is lost. Write down every value before you touch it.
Which Carel IR33 Do You Have?
Before you follow any steps, read the label. The name IR33 covers more than one product, and the key presses and codes differ.
| Controller | Password and codes |
|---|---|
| IR33+ and IR33 (refrigeration) | Password 22. Parameters use short codes such as St, rd, dI, dt1, AL and AH. Probe errors show as E0 and E1 |
| IR33 / DN33 Universale (universal) | A different controller. One published manual uses password 77 and codes such as St1, c0 and P1, with alarms shown as E01, E02 and so on |
If your codes look like E01 and P1 instead of E0 and dI, you have the universal version, so use its own manual. The rest of this guide is for the refrigeration IR33.
How to Enter the Carel Controller Password
Parameters come in two types. Type F (frequent) parameters, including the set point St, are easy to reach. Type C (configuration) parameters sit behind the password. Carel's IR33+ manual describes it like this:
- From the normal temperature display, press and hold Prg/Mute for more than 3 seconds. The display shows PS (password) with 0.
- Press UP until the display reads 22.
- Press SET. The first configuration parameter appears. The display shows the parameter code.
- Use UP and DOWN to scroll to the code you want, then press SET to see its value.
- Change the value with UP and DOWN, then press SET to confirm.
- Hold Prg/Mute for about 5 seconds to save and exit.
Older IR33 units and some programming sheets say to press Prg and SET together for more than 5 seconds, then scroll the 00 on the display to 22. Both methods lead to the same password screen, so if one doesn't work, try the other. If you stop pressing keys the controller times out and drops the unsaved changes, and switching it off before you save does the same.
About the password: the manuals we checked don't describe a parameter for changing it, and they give 22 as the password. If 22 is rejected, the unit may be a universal IR33, a custom build from the cooler's manufacturer, or one with a locked keypad. Check the model on the label before you try anything else.
Carel IR33 Keys and What They Do
| Key | What it does |
|---|---|
| SET (hold 1 s) | Shows the set point St. UP and DOWN change it, SET stores it |
| Prg/Mute | Opens the parameter menu when held. Silences the buzzer on an alarm. Holding it for 5 seconds saves changes |
| UP / DOWN | Scroll through codes and change values |
| DOWN/DEF or SET/DEF (hold 5 s) | Starts a manual defrost. The marked key depends on the model |
How to Change the Set Point
- Press and hold SET for more than 1 second. The display shows St, then the current value.
- Press UP or DOWN to change it.
- Press SET to save it.
The factory set point in Carel's manual is 0 °C, which is only a starting value. Installers usually set it to suit what the room holds, for example a few degrees above zero for a coolroom or well below zero for a freezer. If you're not sure, check the product's storage requirements before changing it.
Carel Controller Parameters Explained
Parameters are grouped by the first letter of the code, which makes the list easier to read. The differences between models are large, so we only list defaults that appear in Carel's own manual. For all the others, the value you see on your controller is the one your installer set, and that is normal.
| Group | What it covers |
|---|---|
| / | Probes: type, calibration, which probe does what |
| r | Control: set point limits and the differential |
| c | Compressor: delays and minimum on and off times |
| d | Defrost: type, interval, end temperature, maximum time, drip time |
| A | Alarms: high and low limits, delays, digital inputs |
| F | Evaporator fans |
| H | Other settings: serial address, buzzer, keypad lock |
Temperature control
| Code | What it does | Factory default |
|---|---|---|
| St | Set point, the temperature you want to hold | 0 °C |
| rd | Differential. The compressor restarts this far above the set point | Varies by model |
| r1 / r2 | Lowest and highest set point a user can enter | Varies by model |
| r4 | Night-time set point change, used with a night input | 3 |
| /c1 | Calibration of probe 1, from -20 to 20 | 0 |
| /A2 | What probe 2 does. 2 means the defrost probe | 2 |
Compressor protection
| Code | What it does |
|---|---|
| c1 | Shortest time between two compressor starts |
| c2 | Shortest time the compressor stays off |
| c3 | Shortest time the compressor stays on |
| c7 | Maximum pump-down time (default 0, so pump-down is off) |
Defrost
| Code | What it does | Factory default |
|---|---|---|
| d0 | Defrost type, for example heater or hot gas | Varies by model |
| dI | Time between defrosts. 0 means no automatic defrost | 8 |
| dt1 | Temperature at which the defrost probe ends the defrost | Varies by model |
| dP1 | Longest a defrost is allowed to run | Varies by model |
| dd | Drip time after defrost, before cooling restarts | Varies by model |
| d5 | Delay before a defrost starts at power-up or from the digital input | 0 |
| d6 | What the display shows during defrost | 1 |
| d8 | High temperature alarm bypass time after a defrost | 1 |
A defrost works like this: every dI interval the controller starts a defrost, the heater or hot gas runs, and it stops when the defrost probe reaches dt1 or when the time dP1 is up, whichever happens first. If frost keeps building up, those settings are the first thing to check, along with the heater itself. Our guide to a freezer not defrosting with ice build up lists the parts to test, and the defrost heater testing guide shows the multimeter steps.
Alarms, fans and other settings
| Code | What it does | Factory default |
|---|---|---|
| AL / AH | Low and high temperature alarm limits | Varies by model |
| Ad | Delay before a temperature alarm sounds | Varies by model |
| A4 / A5 | What digital input 1 and 2 do, for example a door switch or external alarm | 0 |
| A6 | How long the compressor stops after an external alarm | 0 |
| A7 | Delay before the digital alarm input acts | 0 |
| F0 / F1 | Evaporator fan control and the temperature at which the fan starts | Varies by model |
| H0 | Serial address for a supervisor system | 1 |
| H6 | Keypad lock, sum of the keys to disable | 0 |
Don't copy settings from another room. One manufacturer's published programming sheets list quite different set points, defrost intervals and alarm limits for each cabinet type. The right values depend on the evaporator, the defrost method and what is stored, so use the sheet from your own equipment's manufacturer or installer.
Carel Coolroom Controller Settings: What to Check
The IR33 is a general refrigeration controller, so a Carel coolroom controller is the same unit with a coolroom setup loaded by whoever built the room. If the room is warm, icing up or alarming, check these in order:
- The set point St, and whether the display is actually showing it.
- The defrost settings dI, dt1 and dP1. A defrost that is too short leaves ice on the coil, while one that ends on time-out every cycle can point to a defrost probe that isn't reading properly.
- The alarm limits AL and AH, and the delay Ad, so you don't get false alarms or miss real ones.
- The probes. A probe reading wrong causes more coolroom problems than a faulty controller. Look at the wiring before you change any parameter.
- The door switch input and light settings, if the room has them.
For the coil, fan and heater side, start with our commercial fridge parts collection.
Defrost and Reset: Manual Defrost and Factory Settings
Manual defrost
Hold SET/DEF (or DOWN/DEF, depending on the model) for more than 5 seconds. The controller starts a defrost only if the defrost probe is below the end-of-defrost temperature. If the coil is already warm it won't run, which is normal. While defrosting, the display can show dEF.
Restore factory defaults
- Switch the controller off.
- Hold the Prg key.
- Switch the power on while still holding Prg, until the display shows Std (about 5 seconds).
This wipes every change and loads the manufacturer's default set. On a coolroom that was set up by an installer, that can leave the room without its defrost and alarm settings. Photograph or write down all values first. Some units hold several default sets (the Hdn parameter), in which case the display asks you to pick one.
Carel IR33 Alarm and Display Messages
| Message | What it means |
|---|---|
| E0 | Probe 1 fault (the control probe). The alarm resets by itself when the probe reads normally |
| E1 | Probe 2 fault. On most setups probe 2 is the defrost probe |
| EE | Memory (EEPROM) error in the unit parameters |
| EF | Memory (EEPROM) error in the operating parameters |
| dEF | Defrost in progress. Not a fault |
| dFb / dFE | Manual defrost has started / has finished |
| dA / IA | Delayed / immediate external alarm from a digital input |
| Std | Default parameters have been restored |
E0 and E1 almost always trace back to a probe, its wiring or a loose connector, so check those before you replace the controller. If E1 shows and the controller was never fitted with a second probe, the probe 2 setting (/A2) may need to be set to not fitted, along with the defrost type and fan settings that depend on it. Check the manual for your model before you make that change. EE and EF are a memory fault. Re-enter and save the parameters, and if the error returns, the controller needs service.
If your fridge shows E1 and you're not sure whose controller it is, or you have a Bromic or Skope unit with a different code, our commercial fridge controller error codes guide goes through each one. If the controller has a Dixell badge instead, read our Dixell XR60CX settings guide.
Carel IR33 Manual: Where to Find It
Use Carel's own documentation for your model, because the code list and defaults vary. The manual we used for this guide is Carel's IR33+ user manual. Zero Zone also publishes a Carel IR33+ programming sheet with its cabinet settings. The part number on the label tells you which one applies.
Replacing or Mounting a Carel Controller
If the controller has failed, check the supply voltage and relay rating on the label, the probe type (NTC or PTC) and the size of the panel opening before you order a replacement. Write down the settings first so they can be copied across. We don't list the IR33 itself right now, but these related parts are in stock:
- Controller mounting box for Dixell, Carel and Elitech controllers - a pre-cut plastic box for a neat install. Check your controller's size against the opening before you order.
- Elitech EK-3030 coolroom controller - a low and medium temperature coolroom controller. It is a different make, so compare the cut-out, outputs and wiring before you swap.
- Backup relay 30A 3HP 240V - for loads above the controller's relay rating.
Browse more in our refrigeration temperature controllers, or send your controller label to the Find Your Part page.
Safety: controllers and the equipment around them run on mains voltage. Isolate the power before you open anything. Wiring and relay changes should be done by a licensed electrician or refrigeration mechanic, and any refrigerant work needs an ARC licensed technician.
Frequently Asked Questions
What is the Carel IR33 controller password?
The configuration password on the Carel IR33 and IR33+ refrigeration controllers is 22. You enter it by holding Prg until the display shows 0 (or PS), pressing UP until it reads 22, then pressing SET. A universal IR33/DN33 uses different codes and a different password, so check the model first.
How do I enter the Carel IR33 parameters?
Hold Prg/Mute for more than 3 seconds, scroll to 22 with UP, press SET, then use UP and DOWN to find the code. Press SET to see the value, change it, and hold Prg for about 5 seconds to save.
How do I change the set point on a Carel IR33?
Hold SET for more than 1 second. The display shows St and the current value. Change it with UP or DOWN and press SET to save.
How do I reset a Carel IR33 to factory settings?
Switch the controller off, hold the Prg key, and switch it back on while still holding it. Release when the display shows Std, which takes about 5 seconds. This removes every change, so record your settings first.
How do I start a manual defrost on a Carel IR33?
Hold the SET/DEF or DOWN/DEF key for more than 5 seconds, depending on the model. The defrost runs only if the defrost probe is below the end-of-defrost temperature.
What does E1 mean on a Carel controller?
E1 is a probe 2 fault. On most refrigeration setups probe 2 is the defrost probe, so check its wiring and connector first. E0 is the same fault for probe 1, the control probe.
Is a Carel coolroom controller different from an IR33?
The IR33 is a general refrigeration controller used in many coolrooms. A coolroom controller is usually an IR33 loaded with settings for that room, so the parameter values depend on who set it up.
Where can I find the Carel controller IR33 manual?
Carel publishes the IR33+ user manual on its website, and we link to it in this guide. Use the manual that matches the model code on your controller label.
Need Help With a Commercial Fridge Controller?
Settings are only half the job. If the display shows an error or the room won't hold temperature, check the probe, fans and defrost parts too. Send your controller model and a photo of the label to sales@fastfridgespares.com.au or call 0405 972 558 and we will help you find the right part.
Sources: Carel IR33+ user manual, Zero Zone Carel IR33+ programming sheet, Hawco Carel IR33 user manual.