Understanding exactly how your household unit functions is the key to its long and trouble-free operation. The refrigerator Minsk MHM 162 is a classic example of a two-chamber system with full automation of defrosting processes, known as No Frost. Unlike older models, where it was necessary to manually turn off the device to remove ice, here all processes are controlled by electronics and thermodynamic laws.
The main task of the device is to transfer heat from the internal volume of the chambers to the external environment, which is achieved through the circulation of the refrigerant. Refrigerant, passing through a system of tubes, it constantly changes its state of aggregation, sometimes evaporating, sometimes condensing, which allows it to maintain a given temperature. It is important for the owner to realize that cold is not “created,” but heat is “taken” from the food and air inside the cabinet.
This model implements a circuit with one compressor, which serves both chambers at once through a system of bypass valves and dampers. This engineering solution allows you to optimize energy consumption, although it imposes certain restrictions on the independence of temperature conditions in the freezer and refrigerator compartments. Let us examine in detail each component of this complex mechanism.
Design and role of the compressor unit
The heart of any refrigeration circuit is the compressor, which in the model MHM 162 is usually installed in the lower rear part of the housing. This is a sealed piston-type motor-compressor, the task of which is to compress gaseous freon and forcefully pump it through a pipeline system. It is the pressure created by this unit that forces the refrigerant to move, overcoming the resistance of narrow capillary tubes.
It is important to note that the compressor does not operate constantly, but cyclically, turning on by a signal from the thermostat or electronic control module. Operation cycle directly affects engine service life and device noise level. When the temperature inside the chambers reaches the set values, the circuit breaks and the motor stops until the next temperature increase.
⚠️ Attention: If you hear a loud knock or hum when starting the motor, this may indicate a problem with the starting relay or wear of the piston group. Do not ignore the change in the sound profile of the compressor.
To protect against overheating and voltage surges, the design includes special thermal relays. They open the power circuit if the temperature of the motor windings exceeds critical values. The model Minsk 162 often uses compressors of the brand Atlant or Secop, which have proven themselves to be reliable units that can operate for decades provided there is a stable voltage in the network.
Refrigerant circulation system and heat exchange
After leaving the compressor, highly compressed and heated freon enters the condenser. In refrigerators MHM 162 the capacitor is most often made in the form of a steel sheet welded to the rear wall of the case, or in the form of a coil openly located at the rear. Here the condensation process occurs: the gas gives off heat to the surrounding air and turns into a liquid state.
Next, the liquid refrigerant passes through a filter-drier, where moisture is removed from it, preventing the formation of ice jams, and enters the capillary tube. Capillary tube has a very small diameter, which creates the necessary resistance for a sharp drop in pressure before entering the evaporator. It is this pressure difference that allows freon to boil at very low temperatures.
The evaporator in this model is located behind the rear panel of the freezer. Passing through its channels, the refrigerant actively boils, taking heat from the internal volume. The air from the chambers is driven by a fan through the evaporator, cooled and returned back. Such a system forced circulation ensures uniform distribution of cold and the absence of zones with elevated temperatures.
| System unit | Function | Temperature mode |
|---|---|---|
| Compressor | Compression and pumping of gas | Heating to 70-90°C |
| Condenser | Heat release to the room | Warm to touch |
| Capillary tube | Flow throttling | Quick cooling |
| Evaporator | Heat absorption from chambers | Up to -25°C and below |
Operating algorithm of the No Frost system
The main feature of the model Minsk MHM 162 is the absence of the need for manual defrosting. The system No Frost (translated as “without frost”) is implemented through a special algorithm for defrosting the evaporator hidden behind a plastic panel in the freezer compartment. Humidity from the air settles precisely on this hidden heat exchanger, and not on the products or walls of the chamber.
The defrosting process starts automatically at certain intervals, which are counted by the compressor, or by a timer signal. At this moment, the Defrost heating element (tubular electric heater) located under the evaporator turns on. It heats the radiator, melting the frozen ice.
Where does the water go during defrosting?
The resulting water flows down a groove into a special hole located in the lower part of the rear wall of the freezer. Through a system of tubes it enters a plastic container (bath) mounted above the compressor. There, the water evaporates naturally due to the heat given off by the operating motor-compressor. There is no need to add water or empty this pan manually.
This process is controlled by a defrost sensor (defrost timer or electronic module). As soon as the ice has completely melted and the sensor temperature rises above a certain threshold, heating stops. This is followed by a pause necessary for the heating element to cool down before the compressor starts cooling again. This prevents sudden changes in temperature inside the chambers.
⚠️ Attention: If you notice an ice “coat” on the back wall inside the freezer, this is a sign of a malfunction of the defrost system. The heating element may have burned out, the sensor has failed, or the drainage hole has become clogged.
Temperature control and thermoregulation
Maintaining the set temperature in the refrigerator MHM 162 is carried out using a mechanical or electronic thermostat. Mechanical models use a bellows tube that is sensitive to changes in air temperature in the refrigerator compartment. When the gas expands or contracts inside the tube, the electrical contacts close or open.
In more modern modifications or versions with electronics, control is carried out via electronic control unit. It receives data from thermistors (thermistors) installed at different points in the chambers. This allows you to more accurately maintain the temperature and diagnose malfunctions by displaying an error code on the display or signaling by flashing indicators.
The user can adjust the cooling intensity using the rotary knob or buttons on the front panel. Air duct damperconnecting the freezer and refrigerator compartments opens and closes automatically or manually (depending on the modification), passing cold air from the freezer into the upper compartment.
- ❄️ Power adjustment allows you to adapt the operation of the refrigerator to the number of loaded products.
- 🌡️ The thermostat protects the system from overcooling by turning off compressor when the minimum is reached.
- 🔄 Air circulation is ensured by a built-in fan that operates synchronously with the compressor.
Ventilation and distribution of air flows
The efficiency of the refrigerator Minsk 162 directly depends on proper air circulation. The freezer compartment has a fan that blows air onto the evaporator. Cooled air enters the refrigerator compartment through special channels and is distributed among the shelves.
It is important to understand that for normal operation of the system it is necessary to leave free space between the products and the back wall. If you tightly hammer the chamber to the very top, blocking the outlet openings of the air ducts, circulation will be disrupted. This will cause the sensors to read the wrong temperature, and in some areas the food may spoil.
In addition, the ventilation system requires the presence of gaps between the shelves. Cold air is heavier than warm air, so it sinks, displacing warm air upward, where it is again captured by the cooling system. Violation of this natural or forced exchange leads to the formation of condensation and uneven cooling.
☑️ Checking the ventilation system
Typical problems and their connection with the device
Knowing the principle of operation, it is easier to diagnose malfunctions. For example, if the refrigerator MHM 162 runs continuously without turning off, this may indicate a freon leak or loss of compressor performance. The system tries to compensate for the lack of cold by working in enhanced mode, but cannot reach the set temperature.
The appearance of water on the floor is often associated with a clogged defrost drainage system. The melt water does not go into the pan, but overflows over the edge of the gutter and flows out. In this case, it is necessary to clean the drainage hole, often it is enough to use a soft wire or a syringe with warm water.
Noisy operation or vibration can be caused by improper installation (feet not adjusted), tubes touching each other or loosening of the compressor fastenings. Vibration transmitted to the body and amplified, creating discomfort. Also, the source of noise may be a faulty fan, the bearings of which have gotten dust or ice.
⚠️ Attention: Self-repair of the freon circulation system (refilling, soldering tubes) requires special equipment and a license. Intervention in the sealed circuit without skills will lead to final breakdown of the unit.
Operating rules to extend service life
In order for the refrigerator Minsk MHM 162 to serve for a long time, it is necessary to follow the basic operating rules dictated by its design. Do not load hot food into the chambers. A sharp jump in temperature and humidity will cause the No Frost system to work with overload, building up a huge layer of ice on the evaporator, which the heating element may not be able to cope with.
Regularly check the rubber seals on the doors. If they do not provide a tight seal, warm, moist air constantly enters the chamber. This leads to frequent starts of the compressor and freezing. Wipe the seal with a soft cloth and, if necessary, treat it with silicone grease for elasticity.
Once a year, it is recommended to completely defrost and wash the refrigerator, even despite the No Frost system. This is necessary for sanitizing and cleaning hard-to-reach places from dust and bacteria that cannot be removed automatically. Before washing, be sure to disconnect the appliance from the power supply.
Why does the MHM 162 refrigerator make a lot of noise when turned on?
Noise when turned on often associated with the operation of the compressor or fan. If the buzzing is short-lived, this is normal. A persistent loud noise may indicate that the tubes are touching the housing or each other, or that the fan bearings are worn out. Also check that the refrigerator is level on the floor.
How often should automatic defrost occur?
Depending on the model and settings, the defrost cycle in a No Frost system usually starts every 8-12 hours of compressor operation. This process lasts about 15-20 minutes. At this time, the compressor is stopped, and you can hear a quiet crackling sound or the sound of pouring water.
Is it possible to install MXM 162 close to the wall?
No, it is not possible. For efficient operation of the condenser, which in this model is often located in the walls of the case or at the back, free air flow is necessary. The minimum gap from the back wall to the furniture or wall should be at least 5-7 cm for normal ventilation.
What to do if it is too cold in the refrigerator compartment?
First of all, check the thermostat settings. If they are normal, the air duct damper may be stuck open, and too much cold air from the freezer is entering the chamber. Also, the cause may be a malfunction of the temperature sensor.
Is the refrigerant in the Minsk refrigerator safe?
Yes, modern models use refrigerants (for example, R600a) that are safe for humans during normal operation. However, they are flammable in high concentrations if leaked in a confined space. Therefore, it is strictly forbidden to open the pipelines yourself or try to seal them without pumping out freon.