The through-vane type compressor has a temperature switch that detects the refrigerant temperature on top of the compressor. If the refrigerant temperature becomes excessively high, the bimetal in the switch deforms and pushes the rod upward to open the contact of a switch. As a result, current doesn’t pass through the magnetic clutch, which stops the compressor. Thus the compressor seizure is prevented.
Compressor oil is necessary to lubricate the moving parts of the compressor. Compressor oil lubricates the compressor by dissolving in the refrigerant and circulating throughout the refrigeration circuit. For this reason, the recommended oil must be used.
The compressor oil used in the R-134a system is not interchangeable with the one used in the R-12 system. If the wrong type of oil is used, it may lead to compressor seizure.
2.Compressor oil quantity
If an insufficient amount of compressor oil is present in the refrigeration circuit, the compressor cannot be lubricated thoroughly. On the other hand, if this amount is excessive, a large portion of the oil will coat the inner walls of the evaporator, preventing the efficient exchange of heat and reducing the system’s cooling capability.
For this reason, it is important to maintain the specified amount of oil in the refrigeration circuit.
3.Replenishing oil after parts replacement
Once the refrigerant circuit is opened to the atmosphere, the refrigerant will vaporize and be discharged out of the system. However, since the compressor oil does not vaporize at room temperature, almost all of it will remain in the system. For this reason, when replacing a component such as the receiver/dryer, evaporator, or condenser, an amount of oil equivalent to that contained in the old component must be added to the new component.