Correctly setting the temperature in a refrigerated display case is a critically important step for any entrepreneur involved in the trade of perishable products. Incorrectly set parameters can lead not only to product damage and financial losses, but also to serious fines from sanitary services. Owners of cafes, shops and markets must clearly understand how their equipment functions in order to ensure that the quality of the product is maintained throughout the entire period of sale.
The adjustment process can vary significantly depending on the equipment model, the type of refrigerant and the installed control system. Modern digital controllers allow you to set the mode with an accuracy of a degree, while older mechanical thermostats require more fine-tuning through trial and error. Understanding the principles of operation thermostat and knowledge of the permissible temperature ranges for various groups of products is the basis necessary for the effective operation of commercial refrigeration equipment.
In this article we will analyze in detail the setting algorithms for various types of display cases, consider the nuances of operation in different climatic conditions and answer frequently asked questions from users. You will learn why it is important not just to turn the knob, but to control the actual temperature inside the chamber using independent devices. This knowledge will help extend the service life compressor and avoid emergency situations.
The influence of the type of products on the choice of temperature mode
The first step before setting up should always be to determine the type of product that will be stored in the display case. Different groups of goods require strictly defined storage conditions, violation of which leads to the rapid proliferation of bacteria or loss of presentation. For example, dairy products and meat have different critical points of freezing and proliferation of microflora, which dictates its requirements for microclimate inside the chamber.
There is a generally accepted standard according to which the temperature in the refrigeration chamber must be maintained in the range from 0 to +6 degrees Celsius. However, for confectionery products with cream, the upper limit is often reduced to +4 degrees, and for storing frozen semi-finished products in low-temperature display cases, a regime below -18 degrees is required. Ignoring these standards can lead to the fact that the product will formally be stored in the cold, but will actually begin to deteriorate.
⚠️ Attention: Never set the temperature in a regular medium-temperature display cabinet below 0 degrees if it does not have an auto-defrost function or the evaporator is not protected from freezing. This will lead to the formation of an ice crust on the evaporator and equipment failure.
When there is a mixed load, when there are different products in one display case, it is necessary to focus on the most demanding product. If you store milk and vegetables together, the mode is adjusted to the milk, since vegetables can withstand slightly higher temperatures than milk, but not vice versa. It is also important to take into account that the air temperature in the display case and the temperature inside the product are different values, and thermostat usually reacts precisely to the air temperature.
- 🥛 Dairy products: optimal range +2...+4°C
- 🥩 Fresh meat and fish: +0...+2°C
- 🥦 Vegetables and fruits: +4...+8°C (depending on the type)
- 🍰 Confectionery: +2...+6°C
Design and types of thermostats in display cases
Understanding exactly what device controls your refrigerator greatly simplifies the setup task. Modern commercial display cabinets most often use electronic controllers that display the current temperature on a digital display. Such systems, for example models Carel or Dixell, allow you to set precise values and have built-in alarm functions for deviations from the norm.
In older or budget models, mechanical thermostats are still found. They are a rotary knob with a scale, where the numbers usually indicate not degrees, but the conditional cooling power (from 1 to 7 or from Min to Max). In such cases, setting the temperature is done empirically: turn the knob, wait several hours and measure the temperature with a thermometer, repeating the procedure until the desired result is achieved.
Electronic controllers often have several levels of access: user and service. In user mode, you can only change the temperature setpoint, while in the service menu you can configure parameters differential, defrost time and fan operation. Inexperienced users are categorically not recommended to go into the service menu without technical documentation, since lost settings can disrupt the operation algorithm of the entire refrigeration machine.
What is a thermostat differential?
Differential (or hysteresis) is the temperature difference between turning on and off compressor. For example, if the setpoint is +4°C and the differential is 2 degrees, the compressor will turn off at +4°C and turn on again when the temperature rises to +6°C. A differential that is too small will cause the compressor to work jerkily, and a differential that is too large will lead to temperature fluctuations.
Step-by-step instructions for setting up an electronic controller
Let's consider the algorithm of actions for the most common type of equipment - display cases with a digital thermostat. The interface may differ depending on the brand, but the operating logic of most controllers, such as Evco or Eliwell, is based on similar principles. Before starting manipulations, make sure that the display case is connected to the network and is operating normally.
To change the temperature, you usually need to briefly press the set button (often indicated as Set or a thermometer symbol). The display will flash the current setpoint value. Use the Up and Down arrow buttons to select the desired value. After selecting a value, you must confirm the action by pressing the Set button again or waiting for automatic saving after a few seconds.
Setting algorithm:1. Press and release the "Set" button.
2. Wait for the temperature indicator to blink.
3. Use the "+" or "-" buttons to set the desired value.
4. Press "Set" to confirm.
After changing the settings, the compressor may not start immediately if the protection against frequent starts is triggered. This is a normal situation designed to protect electric motor from overload. Some models require you to hold a button for a few seconds to enter the menu and press a combination of buttons to exit. Always check the sticker on the controller body or the product data sheet.
☑️ Setting up an electronic thermostat
Adjusting the mechanical thermostat
Setting up a mechanical thermostat requires more time and patience, since you do not see the exact numbers on the screen. The regulator is usually a rotary mechanism with a scale, where "1" corresponds to minimum cooling (maximum temperature in the chamber), and "7" or "Max" corresponds to maximum cooling. The “0” or “Off” position completely turns off the cooling.
First, set the knob to the middle position, for example, to the number 3 or 4. Leave the display case in an empty or partially loaded state for 4-6 hours. After this time, place a regular household thermometer between the products in the central part of the display case and leave for another 30-60 minutes to stabilize the readings.
If the temperature is higher than necessary, turn the knob towards larger numbers (increasing coldness). If the temperature is too low and there is a risk of food freezing, turn the knob to a lower setting. Each change in the position of the handle must be accompanied by a wait for the temperature to stabilize, which can take up to 12 hours in a fully loaded display case.
⚠️ Attention: When setting a mechanical thermostat, avoid sharp turns of the knob across the entire scale. This may cause the contacts to stick or damage the thermostat bellows tube. Move the regulator smoothly and step by step.
Table of optimal temperatures for different products
For ease of use, it is recommended to have a memo with recommended storage temperatures on hand. This will help you quickly navigate when changing the assortment or receiving a new batch of goods. Below is a table that serves as a guide for setting refrigeration equipment.
| Product type | Optimal temperature (°C) | Permissible fluctuation | Shelf life (approximate) |
|---|---|---|---|
| Dairy products | +2 ... +4 | ±1°C | up to 5-7 days |
| Chilled meat | 0 ... +2 | ±0.5°C | up to 3 days |
| Vegetables (general) | +4 ... +8 | ±2°C | up to 10 days |
| Confectionery | +2 ... +6 | ±1.5°C | up to 3 days |
| Ready cooking | +2 ... +4 | ±1°C | up to 2 days |
It is worth considering that the shelf life is indicated for ideal conditions. In a real retail outlet, where the display is often opened, the temperature may rise briefly. Therefore, it is recommended to keep the setpoint closer to the lower limit of the permissible range, but without crossing the freezing line.
Common mistakes and methods for eliminating them
One of the most common mistakes is trying to quickly cool warm foods by setting the lowest possible temperature. This leads to the fact that compressor works at the limit of its capabilities without stopping, which causes it to overheat and increase energy consumption, while products at the rear wall can freeze, but in the center remain warm.
Another mistake is loading warm products that are completely empty, but already cooled showcases. A sharp temperature change forces the cooling system to work in extreme mode. It is more correct to prepare the display case in advance by setting the desired mode several hours before loading, or to load the goods gradually.
Sometimes users complain that the display case does not “hold” the temperature. Often the reason lies not in a malfunction, but in improper air circulation. If food is stacked close to the top, blocking the vents or cold air exhaust line, the thermostat will show one temperature, but in reality heat pockets will form in the chamber.
- ❄️ Do not block the vents with food.
- 🌡️ Do not place hot or warm food into the display case.
- 🚪 Minimize the time you open the door or curtain.
- 🧹 Regularly clean the condenser from dust for effective heat transfer.
If you notice that a thick crust of ice forms on the back wall of the display case, and the temperature inside is higher than normal, this is a sure sign that the defrost system is not working correctly or the condensate drain is clogged. In this case, simply resetting the thermostat will not help - defrosting and, possibly, calling a technician are required.
Why does the display case not reach the set temperature?
There may be several reasons: the door does not close tightly (wear of the seal), the condenser is dirty, lack of refrigerant due to micro-leakage or a malfunction of the thermostat. It is also possible that the display case is installed too close to the wall or heat source, which interferes with heat transfer.
Can a household thermometer be used to check?
Yes, a regular alcohol thermometer is quite suitable for monitoring the temperature of products. Electronic kitchen thermometers are also effective. The main thing is not to use mercury thermometers in food areas due to the risk of breakage and contamination of food with toxic fumes.
How often should you check the temperature in the display case?
According to sanitation rules, a temperature log should be kept daily. It is recommended to carry out actual measurements at least twice a day (morning and evening), recording the readings in a special journal.
What to do if the temperature fluctuates?
If the fluctuations are more than 2-3 degrees, check the tightness of the door closure, the absence of drafts from the air conditioner or sunlight falling on the display case. It is also worth checking the operation of the evaporator fans.