When a supermarket cabinet stops cooling, product loss starts within hours. In dairy, meat and ready food, shelf life shortens even when the temperature rises by just a few degrees, and a food safety risk arises. That is why it is important to quickly work out where the problem comes from.
A supermarket cabinet is a commercial refrigeration unit designed to display products within a certain temperature range. Plug-in cabinets with their own compressor and cabinets connected to a central rack work on the same basic principle. The six causes below are the ones we meet most often in the field in both.
What can you check yourself first?
Before calling service, you can check how warm the cabinet really is and whether its surroundings are suitable. These checks are safe and often narrow down the problem.
- Put a calibrated thermometer inside the cabinet, read it after 15–20 minutes and compare it with the value on the display.
- Check whether there are boxes, packaging or a wall in front of the cabinet's rear and lower grilles.
- Check whether products exceed the load line inside the cabinet.
- On cabinets with doors, check whether the door closes fully and whether the gasket is torn.
- If there is an alarm or error code on the display, make a note of it.
Do not reach behind the grille without unplugging the unit, and do not touch electrical connections or copper pipes. Work on the refrigerant circuit and the panel must be done only by a qualified technician.
6 reasons a supermarket cabinet does not cool
01Condenser is dirty or cannot get air
The condenser is the coil that rejects the heat drawn from inside the cabinet; when it is dirty or blocked in front, the cabinet cannot cool. Dust, grease and packaging debris clog the coil, the compressor runs at high pressure and capacity drops.
In plug-in cabinets, the cabinet being pushed against a wall or drawing in the hot air of the cabinet beside it gives the same result. This is the cause of most "doesn't cool in the afternoon" complaints that appear in summer.
02Evaporator is iced up, defrost is not working
If ice has built up on the evaporator, air cannot pass and the inside of the cabinet warms up. Normally the defrost cycle melts this ice at set intervals. If the defrost heater, defrost sensor or timer setting is faulty, the ice grows. Icing is mostly seen together with a humid environment, a door opened often or a clogged drain line.
03Evaporator fan is not turning
The fan distributes cold air among the products; when it stops, the shelves warm up even if the evaporator stays cold. A burnt-out fan motor, ice touching the blades or a faulty door switch can stop the fan. In open multideck cabinets, when the fan stops, the air curtain at the front is also disrupted.
04Air curtain or door gasket is damaged
Open multideck cabinets keep ambient air out with the cold air curtain at their front. When products exceed the load line and block the air outlet and return grilles, the curtain breaks and the cabinet draws in the warm store air.
In cabinets with doors, a torn or hardened gasket has the same effect. Close the door on a strip of paper and pull it; if the paper slides out easily, the gasket is not doing its job.
05Refrigerant is low, there is a refrigerant leak
In a cabinet with a refrigerant leak, the compressor runs continuously but the cabinet does not reach the desired temperature. Only part of the evaporator icing up and oil traces at weld and fitting points are typical signs.
Refrigerant topped up without finding the leak brings the same fault back shortly after. Leak detection and charging must be done by a certified technician in line with the F-gas regulation. For details, see our refrigerant leak and charging service.
06Sensor, control board or compressor fault
Is your cabinet not cooling?
Our team finds the fault by on-site measurement and, if needed, responds the same day.
If the display shows the temperature correctly but your thermometer reads a different value, the sensor may have drifted. When the control board, a relay or the compressor's starting components fail, the compressor either does not run at all or stops and starts often. These cases are diagnosed with a measuring instrument.
Why do ambient conditions matter so much?
Commercial cabinets are designed for a given ambient temperature and humidity; exceeding these limits directly reduces capacity. Cabinet manufacturers usually specify a test class such as an ambient temperature of around 25 °C and a relative humidity of around 60%.
Cabinets where the air conditioning is inadequate, that stand in front of a sunlit window, or that sit next to an oven easily exceed this limit. In such a case, cooling is not enough even if the cabinet itself is sound; the solution should be sought in the space's climate control.
What is different in supermarkets with a central system?
In supermarkets with a central system, the cabinets are fed from a shared compressor rack in the machine room. If only one cabinet is not cooling, the problem is usually in that cabinet's solenoid valve, expansion valve or fan. If several cabinets warm up at the same time, look at the central rack, the condenser or the refrigerant amount.
A similar picture is seen in cold rooms too. We cover selection and installation mistakes on the cold room side in our cold room installation article.
How do you protect the products during a breakdown?
When you notice a cabinet is not cooling, the first thing to do is move the products to another cabinet or a cold room that can hold them at a safe temperature. In the time until service arrives, product temperature keeps rising and the loss grows.
- Move sensitive products (meat, chicken, dairy, ready meals) first.
- Record with a short note what temperature the products were at and at what time; this record is also useful in food safety inspections.
- Do not open the cabinet door unnecessarily, and on open multideck cabinets, pull down the night curtain if there is one.
- Do not try to scrape an iced-up evaporator with a sharp tool; the fins and copper pipes are easily punctured.
When notifying service, giving the cabinet type, brand, the error code on the display and how long the problem has lasted helps the technician arrive with the right part.
What should be done to prevent the fault from recurring?
Most cabinet faults are prevented by regular maintenance. Cleaning the condenser coils generally every 1–3 months in heavy use, clearing the drain line, and checking gaskets and fans eliminate most faults.
At YOİ Mühendislik, we put cabinets, cold rooms and climate control systems in supermarkets and food businesses on the same maintenance plan. We respond to breakdowns as a priority and record the pressure and temperature values measured at every visit. The scope and price of maintenance are determined at the site survey according to the number of units.
Frequently asked questions
Why does a supermarket cabinet stop cooling in the afternoon?
The most common cause is a dirty condenser or one starved of air. As the ambient temperature rises, the condenser cannot reject heat, the compressor runs at high pressure and the inside of the cabinet warms up.
Does adding refrigerant to a supermarket cabinet fix the problem?
Topping up refrigerant without finding and fixing the leak is a temporary fix. The leak point must first be found and repaired, then the system must be evacuated and charged with the correct amount.
How often should a supermarket cabinet condenser be cleaned?
For heavily used cabinets and those in dusty environments, cleaning every 1–3 months is generally recommended. This interval can vary with ambient conditions.
What causes icing in the cabinet?
A faulty defrost heater, defrost sensor or timer setting, a clogged drain line, a door opened too often and a damaged gasket all cause icing.