Freezer common fault, how to check whether the true fault?

I. Common failure phenomena of commercial freezer:
1. Leakage of refrigerant, electrical (Circuit, body)Leakage caused by insulation damage, etc.
2. The cooling system is dirty and blocked, and the condenser is Dusty.
3. The wire is disconnected, the fuse is blown, the overload protector contact is disconnected due to overheating or overcurrent, and the pressure relay contact is disconnected due to abnormal pressure of the refrigerator refrigeration system.
4. Compressor motor winding, fan motor winding, solenoid valve coil, relay coil and contact burned.
5. The compressor is stuck, the moving parts are stuck, and so on.
6. Compressor valve damage, piston pull, fan blade damage and various components damage. Second, how to check whether the freezer is faulty
whether the surface of the freezer is too dirty? Didn't the freezer defrost for a long time? Is the freezer not broken? Is the power supply of the commercial freezer undamaged or is the power supply turned off? Whether the temperature set by the switch is appropriate; Whether there are obstacles in front of the freezer; The refrigerating capacity of the freezer is too small and needs professional inspection;
whether the freezer uses heating elements, such as heating equipment; Whether there is strong sunlight entering and directly illuminating the surface of the freezer; Whether there is a lack of certain substances in the commercial freezer; Is there any unknown substance in the freezer.
Some phenomena in use seem to have problems, but this is not a fault. Therefore, when the cooling effect is not satisfactory, the above reasons are excluded first.
Don't mistake the normal phenomenon for a fault, and rush to ask after-sales personnel to repair it and spend some money; Some phenomena are caused by improper operation and users should be able to adjust themselves. It is common for freezers to lack refrigerant and the control circuit cannot work properly. The thermal protection function of the press does not work, the press is damaged, the external fan does not rotate, the external condenser is too dirty, the pipe is blocked and other reasons do not cool.