How to judge whether the freezer is normal?

carefully observe the working conditions of each component of the commercial freezer, focusing on the three parts of the refrigeration system, electrical system and air system to judge whether they work normally.
1. Refrigeration system: observe whether there are cracks, damages, frosting and condensation in each pipeline of the refrigeration system; Whether there is collision and friction between refrigeration pipelines, pipelines and shells, etc. , especially at the welding of refrigerant pipelines, whether there is leakage at the joint, and there will be oil stain at any leakage (There is a certain amount of refrigerating oil in the refrigeration system) , Can also use clean soft cloth, soft paper to wipe the pipeline welding and joint connection, observe whether there is oil stain, to judge whether there is leakage.
2. Electrical System: observe whether the fuse of the electrical system is blown, whether the insulation of the electrical conductor is intact, whether the circuit board is broken, whether the connection is loose, etc. In particular, whether the electrical connection is in good contact, the wiring screws and connectors are easy to loosen and cause poor contact.
3. Ventilation system: observe whether there is too much dust on the air filter screen, heat exchanger coil and fins; Whether the air inlet and air outlet are unblocked; Whether the fan and fan blades are running normally; Whether the wind power is normal, etc.