The situation when refrigerator buzzing without interruption immediately after the technician’s visit causes the owner panics and bewilders. It would seem that the problem should have disappeared, but the unit only changed the nature of the noise to continuous operation of the compressor. This is a common scenario that can indicate both a natural stabilization process and gross errors when installing spare parts.
It is important to understand that cooling cycle is a complex mechanism where each element affects the other. If, after replacing the thermostat or filling with freon, the equipment no longer turns off, it means that the temperature or pressure balance in the system is disturbed. Ignoring the problem in the first hours it can lead to overheating of the engine and the need for repeated, more expensive repairs.
Do not immediately accuse the specialist of incompetence, but the situation cannot be left unattended. In the first 6-12 hours after a deep repair (especially with the replacement of the compressor or refrigerant), the refrigerator can work in enhanced mode to reach the initial temperature. However, if this mode lasts a day or more, it is necessary to look for the technical cause of the failure.
Natural reasons for the continuous operation of the unit
There are a number of factors in which continuous operation the compressor is a normal reaction of equipment to intervention in the system. After defrosting or replacing components, the temperature inside the chambers is significantly higher than normal, and the automation gives the command for maximum power.
If carried out Freon charging, the system requires time to reach operating mode. The refrigerant must circulate completely through the circuit, and the evaporator must cool to the specified parameters. During this period, sensors record heat and prevent the compressor from going into sleep mode.
- 🧊 Temperature set: If the chambers have been completely defrosted, it may take from 2 to 6 hours to cool the empty volume.
- 🌡️ Thermal inertia: Sensors may indicate incorrect data until the heat exchange between the walls of the chambers and the air stabilizes.
- 🚪 Load density: An empty refrigerator or, conversely, filled with warm food will work longer than usual.
⚠️ Attention: If after 12 hours of continuous operation, the temperature in the main chamber is above +5°C, and in the freezer above -18°C, which means that the system does not cool, but simply circulates air. This is a sign of a malfunction, not an adaptation.
It is also worth considering seasonality. In hot weather or when installing a refrigerator next to (battery, stove), heat dissipation difficult. After repair, when the system is already under stress, external factors can prevent timely shutdown.
Errors when installing the thermostat and sensors
The most common reason the refrigerator does not turn offis incorrect installation of the thermostat. This element is responsible for opening the compressor power circuit when the desired cold is reached. If the technician installed the wrong model or incorrectly secured the sensing bulb (heat-sensitive flask), the shutdown will not occur.
The thermostat must fit snugly against evaporator or a special area on the back wall of the chamber. Gaps, lack of thermal paste or weak fastening lead to the fact that the sensor does not “feel” real cold. It continues to signal the controller about the need for cooling, even when the temperature inside is already sub-zero.
In models with electronic control (No Frost), the situation is complicated by the presence of air sensors. If a wire is pinched or the connector is damaged during assembly, the control unit may receive false signals about high temperature. A data reading error blocks the command to stop the motor.
Sometimes the problem lies in the adjustment. Some thermostats have calibration screwwhich allows you to shift the response range. If during repairs it was turned without a pressure gauge and thermometer, the range could go astray towards infinite cooling.
Problems with the refrigerant and circulation system
Quality filling with freon is an art that requires precision. If after repair the refrigerator hums, but does not cool (or cools weakly) and does not turn off, the refrigerant balance in the system may be imbalanced. This is a critical situation that requires professional intervention.
Insufficient quantity freon leads to the compressor running, but the pressure in the system does not reach the values required to stop. The sensors see that the temperature is not falling and keep the motor running. In this case, heating of the condenser only in the lower part or its complete cooling may be observed.
The opposite situation is refilling. Excess refrigerant creates high pressure, the compressor is overloaded and cannot shut down because the cycle does not complete correctly. This is often accompanied by whistling sounds and a very hot case.
| Symptom | Possible cause | Action |
|---|---|---|
| Buzzing, but not cold | Freon leak / Blockage | Call a technician to find a leak |
| Humming, slightly freezing | Lack of freon | Refilling and vacuuming |
| Humming, very cold | Thermostat is faulty | Replacing the temperature sensor |
| Humming, hot condenser | Refilling / Air in system | Draining freon and refilling |
Also, the presence of air plug or moisture in the system cannot be ruled out. If high-quality evacuation was not carried out during repairs, residual air or water violates the thermophysical properties of the mixture. Water can freeze in the capillary tube, creating an ice plug that either allows freon to pass through or blocks it.
Failures of the control module and start relay
Modern refrigerators are controlled by complex electronics. If after replacing the compressor or other components the unit does not turn off, the problem may lie in the “brains” of the device. The control module could receive a voltage surge during repairs or be initially faulty.
In such cases relay it may stick in the "on" position. Even if the sensors send a stop signal, the physical contact inside the relay remains closed. This often happens when using non-original spare parts or when installing parts from another model of equipment.
Software failure is another reason. The electronic unit may have become stuck in the defrost or cool cycle. Resetting errors through diagnostic mode or completely de-energizing for a long time (more than 30 minutes) sometimes helps to reboot the controller logic.
⚠️ Attention: If you hear frequent clicks of the relay when trying to start or stop, but the compressor does not respond properly, immediately turn off the device. A stuck relay can lead to burnout of the motor windings.
Checking the module requires diagnostic equipment. The master must read error codes if they are displayed on the display, or ring the output circuits on the control board. Replacing the board yourself often does not solve the problem if the cause of the power surge has not been eliminated.
The influence of seals and chamber tightness
Paradoxically, after repair the problem may lie not in the internal components, but in tightness cabinet. If the technician removed the doors to access the hinges or carried out work near the seal, he could damage the rubber band or screw the door poorly.
The constant influx warm air from the room does not allow the temperature inside to drop to the set value. Sensors detect the heat and keep the compressor running. This is easy to check: run your hand along the perimeter of the door - there should be no noticeable cold air flow outward.
- 🔍 Visual inspection: The seal should fit snugly around the entire perimeter without gaps or waves.
- 📄 Test with paper: Pinch the sheet of paper with the door. If it pulls out without force, the seal is broken.
- 🌬️ Ventilation check: Make sure that the ventilation holes have not been blocked after repair (especially in No Frost models).
Sometimes when replacing compressor technicians forget to check the integrity of the thermal insulation or accidentally crush it, creating “cold bridges”. This forces the equipment to work harder, trying to compensate for losses.
☑️ Checking the tightness after repair
What should the owner do: algorithm of actions
If you are faced with the fact that refrigerator does not turn off after service intervention, follow the algorithm. Don't wait until the engine burns out, but don't panic ahead of time. Primary diagnostics will help to understand the scale of the problem.
First of all, give the equipment time (if less than 6 hours have passed). If the time is up, check your settings. It is possible that the Super Freeze (Super Freeze) or "Vacation" mode was accidentally activated, which blocks the normal shutdown.
If the settings are correct and the refrigerator continues to work:
- Measure the temperature in the chambers with a thermometer.
- Listen to see if the nature of the sound changes (gurgling, hissing).
- Check the heating of the condenser (grid at the back).
- Contact the service that carried out the repair.
⚠️ Attention: The warranty card issued after the repair obliges the technician to eliminate the defects. Do not try to disassemble the unit yourself after professional intervention - this will void your warranty.
In most cases, the problem is solved by calling the technician again to adjust the freon pressure or replace the defective sensor. Timely treatment will save your compressor from overheating and costly replacement.
Is it normal for the refrigerator to hum for 24 hours after replacing the compressor?
On the first day after replacing the compressor and refilling with freon, continuous operation is acceptable. The system should come into operation, cool the entire volume of the chambers and stabilize the pressure. However, if after 24 hours the temperature has not reached normal, this is a sign of a malfunction.
Can a dirty capacitor cause non-shutdown?
Yes, if the back panel was removed during repairs and the condenser was contaminated with dust or hair, heat transfer deteriorates. The compressor overheats and cannot shut down because it does not reach the required condensing pressure. Cleaning is required.
Why, after filling with freon, did the refrigerator become colder and does not turn off?
Most likely, the thermostat adjustment is broken or it is installed incorrectly (not deep enough or without contact with the tube). It is also possible that moisture has entered the system and frozen in the capillary, disrupting circulation.
Is it dangerous to keep the refrigerator turned on for a long time without a break?
For a short time (up to 12 hours) it is not dangerous. Long-term operation without stopping leads to overheating of the compressor windings, destruction of the oil and eventual jamming of the piston group. This reduces the service life of the motor significantly.
Who should pay for a repeat call if the refrigerator does not turn off?
If the problem arose immediately after the repair and is related to the quality of spare parts or the work of the technician (underfilling of freon, defective thermostat), the repeat call and elimination of defects are carried out free of charge as part of the repair warranty.