Investigation and repair of refrigerator refrigeration problems
1 Uncooled caused by motor damage In addition to the voltage is too high and too low caused by the damage of the refrigerator motor, the power supply suddenly stops and the power supply causes damage. Sudden power failure, there is a pressure of 1M Pa in the high pressure chamber of the compressor to the outlet of the capillary, a sudden power failure, causing the piston of the compressor to stop reciprocating. At this time, the pressure in the low pressure section is only 0 02 0 08M Pa, and the pressure in the high pressure section passes. The high pressure valve piece and the low pressure valve piece advance into the piston cavity, so that the pressure in the piston cavity is close to the pressure of the high pressure chamber. If the call is suddenly made, the starting current of the motor will be higher than 8 10 times of the normal working time, or even larger (such as The 125W compressor has an instantaneous starting current of 8A, a starting time of 3-5 seconds, and a normal operating current of 1A), which far exceeds the normal operating current. Therefore, it is often more than the starting time and cannot be started, and it is easy to burn the compressor motor. Check (1) Check the three terminals of the compressor with the multimeter R 1 block, which are common and start, public and work, start and work with each other's DC resistance, taking Beijing Iray brand compressor as an example, respectively 20, 12, 32. (2) If the DC resistance of the motor does not change much, it can be forced to start. A 10mA ammeter is connected in series in the circuit to observe the instantaneous current and working current. (3) Detecting the insulation of the motor to the ground with a 500 megohmmeter. When the burnout is serious, the resistance to ground is 0, and the slight interturn damage to ground is not necessarily 0. Repair firstly discharge the refrigerant in the refrigeration system from the compressor process pipe, respectively weld the high and low pressure system connection pipe, cut the boot casing according to the original data and use the same type of enameled wire winding, or switch the same power model Similar compressors. 2 Failure of refrigeration control caused by failure of control components (1) Turn the thermostat knob, can you hear the switch sound, if not, remove the thermostat, use a multimeter to measure the switch contact, or use the short circuit method to short the two wires that control the compressor work. Power on the refrigerator. If it can start normally, the fault is in the temperature controller. (2) Check the DC resistance of the overcurrent protector and the start relay on and off and the contact. Repair and replace the same specification, the same type of device 3 no refrigeration caused by refrigerant in the refrigeration system The refrigeration system of the refrigerator is composed of two parts, a high pressure section and a low pressure section. If there is a leak at any place, the refrigerator cannot be cooled. Inspection (1) Seeing the oil traces in the leaked area, the Freon can be compatible with the refrigerating machine oil, and the refrigerating machine oil is also brought out in the place where the Freon leaks. The tiny leakage can be seen attached to the leakage. The dust on the surface is shown to be saturated with oil. (2) Touching the hand in the leaked place can leave a trace of oil on the hand. The hand touches the evaporator, and the refrigerator does not feel cool. (3) The ear can hear the normal operation of the refrigerator, but the sound of the freon gas is not heard, and only the sound of the bubble or the sound of the gas passing through the oil can be heard. When the refrigeration system is pressurized with nitrogen, the sound of the airflow can be heard when the leak is large. (4) Pressure inspection There is no oil trace through the inspection of the visible part of the refrigeration system, and there are no obvious signs of smashing, bumping and smashing. It should be suspected that it may be an internal leak. First, the refrigeration system is cut off from the inlet of the capillary, and the cut capillary is sealed at both ends. From the inlet end of the high pressure exhaust pipe condenser capillary to the high pressure end, 1 M Pa of nitrogen was introduced, and the inlet end of the capillary tube of the process pipe compressor return pipe evaporator was the low end, and 0 6 M Pa of nitrogen was introduced. Then check with soapy water in turn, and soap bubbles can be seen in the leaked place. After the pressure gauge valve is closed for 24 hours, the pressure of the watch is observed to see the consistency of the high and low positions, thereby determining the translation, rotation and comparison transformation coefficients required for the registration of the two images with respect to the original position. The search process aligns the centroids of the two image skull regions with the initial search position. From the principle of coarse to fine, first search for several advantages, and then expand at these points to search for extreme points. The interpolation operation is performed using a linear interpolation method. Buy a package evaporator with the same specifications as the bad refrigerator evaporator, installed in the freezer and refrigerating compartment. The freezer is installed by placing two holes with a diameter of 10mm near the bottom and connecting the two main tubes of the main evaporator. Wear it out. The evaporator of the refrigerating compartment must be placed on the last side of the refrigerating compartment, and the two connecting pipes of the sub-evaporator are taken out and connected to the main evaporator, the capillary tube and the low-pressure return pipe respectively, which is advantageous for connecting and reducing leakage. cold. After that, the pressure is checked by the low pressure as the standard. After the leak is confirmed, the system is evacuated and filled with Freon. 4 Unblocked by ice block and dirty block (1) Ice plugs are often replaced with compressors, evaporators, condensers, and dry filters. The vacuum drying process of the refrigeration system is incomplete, and air remains in the refrigeration system. The ice block often occurs at the outlet of the capillary and the evaporator. The biggest feature of the inspection is that when the compressor starts running, the condenser heats up, the evaporator cools and there is gas flowing. After the compressor is operated for a period of time, the condenser does not heat up, the evaporator is not cool, and the sound of gas is not heard, and the compressor is heavy. After the shutdown, the temperature inside the box door is raised, and after the ice is dissolved, the working state is restored to the normal cooling state, but after the refrigerator works for a period of time, it is not hot, not cold, and the sound of the airflow is not heard, so it is repeated. (2) Dirty blockage often occurs at the junction of the dry filter and the capillary, which is the same as the ice blockage, but the difference is that once blocked, it cannot be re-opened. Check that the refrigerator compressor can operate normally, the condenser is not hot, the compressor load is heavy, the evaporator is not cold, there is no gas flowing sound, and there is no periodicity. After the filter is cut, a sufficient amount of refrigerant flows out of the condenser. To repair the ice block and the dirty block, a new dry filter must be replaced, and the refrigeration system should be vacuum dried again. The ice block filter can be reused after drying for 4 hours in a dry box under 200 conditions. The dirty plug of the capillary often occurs at the junction of the filter and the capillary. As long as the dirty plug is cut off, it can be used continuously, or a capillary of the same star can be replaced. Dongguan Yoloon Sports Goods Co.,LtD , https://www.yoloonprotection.com