Cold room not cooling: what should you do in the first 30 minutes?
The first 30 minutes decide how much stock you lose. A closed cold room or freezer room holds its temperature for a long time, an open one loses it fast. Work through the checks in this order and note what you find, so the technician can use it.
1. Protect the stock
Keep the door shut and only open it when you have to. Check the core temperature of the stock with a probe thermometer and move the most sensitive items to another cold room or freezer. Note the times and temperatures.
2. Check power and the breaker
Is the display lit? Look in the distribution board for a tripped breaker or RCD. Reset it once. If it trips again, leave it and call a technician.
3. Check the door and seal
Does the door close fully, and does the seal sit tight all the way round? A door left ajar can push a cold room up several degrees in a short time and ice up the evaporator.
4. Look for ice on the evaporator
The evaporator is the cooling coil with fans inside the room. If it is covered in a thick layer of ice, air cannot get through. Never chip the ice off with tools, as the pipes are easily punctured.
5. Read the display and alarm code
Write down the alarm code or take a photo of the display. The code tells the technician a lot before they arrive. If the system has a Maci tag, scan it and ask the system’s chat what the code means.
6. Check the fans
Are the evaporator fans inside the room running? Is the condenser fan outside running, and is it clear of boxes, leaves or snow? Keep away from fans that are turning.
What can staff check safely, and what is for the technician?
The table shows where the line is. Everything in the middle column can be done by staff without tools and without opening up the system.
| Check | What staff can do | What the technician does |
|---|---|---|
| Power and breaker | See if the display is lit, reset a breaker once | Find the cause if the breaker trips again |
| Door and seal | Close the door, clear obstructions, inspect the seal | Replace the seal, hinges or door switch |
| Ice on the evaporator | See if the coil is iced, start a manual defrost if the manual explains how | Find the cause of the icing and fix the defrost |
| Display and alarm code | Read and photograph the code, look it up in the manual | Fix the fault behind the code |
| Fans | Look and listen for whether they run, clear blockages at the condenser | Replace the motor or fan |
| Refrigerant circuit | Nothing | Everything: pressures, refrigerant, leaks, compressor |
Freezer room not working: what should you do with the stock?
Keep the freezer room door shut. A full, closed freezer room typically holds its temperature for several hours, while every opening lets in warm, moist air. Check the core temperature of the stock and move the items closest to their limit first.
Whether stock has to be thrown away is decided by your HACCP plan: the temperature each product must stay below, and how long it has been too warm. Note times and temperatures as you go. An automatic temperature log shows exactly when the temperature started to rise, which makes the decision easier. See HACCP temperature monitoring.
When should you call an emergency refrigeration technician?
Call a refrigeration technician if the safe checks have not helped within about 30 minutes, or straight away if you see any of these signs:
- The breaker trips again after you have reset it
- The compressor hums, clicks or is silent while the display is calling for cooling
- The display shows a high-pressure or low-pressure alarm, or the same alarm keeps coming back
- You smell burning, hear hissing or see oil at pipes and joints
- The evaporator ices up again shortly after a defrost
- The stock temperature is getting close to the limit in your HACCP plan
Give the technician the system’s name or rating plate, the alarm code, the temperatures and what you have already checked. With a QR or NFC tag from Maci Service, the technician can see the system’s data and service history before setting off, and bring the right part.
Why does a refrigeration system stop? The usual causes
Most breakdowns come down to a handful of faults, and most of them developed for weeks before the system stopped. The table shows the usual causes, the signs, and whether the fault could have been seen in advance.
| Cause | Typical signs | Visible in advance |
|---|---|---|
| Compressor wear | Compressor trips on overload, hums or will not start | Yes, in rising current and longer run times |
| Low refrigerant or a leak | Low-pressure alarm, the room slowly warms up | Yes, in falling suction pressure |
| Icing and defrost faults | Ice on the evaporator, weak airflow, low-pressure alarm | Yes, in defrosts that drag on |
| Dirty condenser or stopped condenser fan | High-pressure alarm, especially on warm days | Yes, in rising pressure and current |
| Evaporator fan fault | No airflow in the room, ice on the evaporator | Often, when the fan wears gradually |
| Electrical fault or power cut | Display off, breaker tripped, contactor burnt out | No, but seen the moment it happens |
| Door left open or a failed seal | Temperature rises fast, ice near the door and on the evaporator | Partly, in temperature swings and run time |
Ice on the evaporator is one of the most common signs. The evaporator ices up when the defrost cannot keep up: a heater has failed, the drain is blocked, the defrost is set wrongly, or the door lets in moist air. In the end air cannot get through, and the room can no longer hold its temperature.
What do high-pressure and low-pressure alarms mean?
A high-pressure alarm means the pressure on the hot side of the system is too high, so the system stops the compressor to protect it. The usual cause is that the condenser cannot get rid of heat: it is dirty, its fan has stopped, or something is blocking the air. Check that the condenser outside is clear, but do not clean it yourself with water or tools.
A low-pressure alarm means the pressure on the cold side is too low. The most common causes are too little refrigerant because of a leak, an iced-up evaporator or a stopped fan in the room. If a leak is behind it, a certified technician has to find and repair the leak before any refrigerant is added. See refrigerant and leaks.
What does a refrigeration breakdown cost?
The repair is rarely the biggest cost. In Denmark, a typical emergency call-out is about 15 minutes of work and costs around 2,700 DKK (about €360) excluding VAT. On top come the stock you have to throw away and the sales you lose while the cold room is empty. If the technician does not have the right part, it becomes two trips.
Our article What does a refrigeration breakdown cost? goes through each cost and has a calculator for your own figures.
Could the breakdown have been seen coming?
Often, yes. Most breakdowns come from faults that develop over weeks: a compressor drawing more current, a suction pressure falling slowly, or defrosts that drag on. The controller’s own alarm only goes off once the temperature is already too high. Our article 5 signs your refrigeration system is about to fail describes the signs.
Sudden electrical faults and mechanical failures without warning cannot be seen in advance. Maci Intelligence detects those the moment they happen and raises the alarm at once. Read more about which faults show in the data and which do not.
How do you avoid the next breakdown?
The best way to avoid the next breakdown is to see it coming. Maci Intelligence measures current, pressure and temperature at several points on the system every minute, learns how that system normally behaves, and typically warns 3 to 6 weeks before a breakdown, with the likely cause. The repair can then be booked in working hours, and the technician arrives with the right part.
If something does go wrong, the right people are told in the app, by SMS and email. If nobody responds within the time you choose, for example 2 hours, the alarm moves to the next person on the list, and your refrigeration contractor can be the one on call. Maci is automated monitoring with escalation. Maci is not a staffed alarm receiving centre. See refrigeration alarm monitoring.
In Maci Service, every system has its own chat with the system’s controller manual and self-help guides in your own language. Staff scan the tag on the system and get help with the alarm code and the safe checks before anyone calls a technician.
Predictive maintenance is covered on the page about predictive maintenance for refrigeration, and refrigeration monitoring explains what is measured. Facility management companies responsible for many clients’ systems can read about refrigeration monitoring for facility management.
Questions and answers
Why do refrigeration systems so often break down at night or at the weekend?
The fault rarely starts that night. It has usually been developing for weeks, and at night or at the weekend nobody notices the room getting warmer. So the damage grows, and the call-out costs more than if the fault had been found earlier.
Does the stock have to be thrown away after a breakdown?
That depends on how warm the stock got and for how long. You decide according to your HACCP plan. An automatic temperature log shows when the temperature started to rise and makes the decision more precise.
What does an emergency refrigeration call-out cost?
In Denmark, a typical call-out is about 15 minutes of work and costs around 2,700 DKK (about €360) excluding VAT. Repairs, parts and sometimes a second visit come on top, and discarded stock is often the biggest cost.
Can we top up the refrigerant ourselves?
No. Any work on the refrigerant circuit, including adding refrigerant, must be done by a certified refrigeration technician. If a system is short of refrigerant, there is a leak that has to be found and repaired first.
How long does a freezer room stay cold after the system stops?
A full, closed freezer room typically holds its temperature for several hours. It depends on the insulation, how much stock is inside and how often the door is opened. Keep the door shut and check the stock temperature.
Who pays if the system is under warranty?
The warranty usually covers repair of the failed component, on the terms given by the installer or manufacturer. Discarded stock and lost sales are rarely covered. Service history and data from the system make a warranty claim easier to document.
Can Maci tell that a breakdown is coming?
Yes, when the fault develops gradually, such as compressor wear, low refrigerant, icing and a dirty condenser. Maci Intelligence typically warns 3 to 6 weeks before a breakdown. Sudden electrical faults cannot be predicted, but Maci raises the alarm the moment they happen.