A good lubricant must have to have the following characteristics:
• Low fat content: The presence of grease, derived oil can clog holes in the system;
• thermal and chemical stability: The oil subjected to extreme temperatures can not suffer decomposition function of temperature nor react with the components present in the cooling system;
• Low pour point: Even in low temperatures, the oil must flow, otherwise there may be lack of lubrication in the compressor as deposits are formed in the system evaporator;
• Low viscosity: The low viscosity is related to the ability of the oil to maintain good lubricating properties at high temperatures while maintaining good fluidity at low temperature points.
Comments:
• To ensure the optimum lubrication properties, lubricating oil manufacturers add chemicals that have the function to reduce and even prevent the emergence of bubbles or sludge. Oil contact with moisture or air promotes the formation of sludge and varnish.
• The oil removed from the system should present clear appearance because discoloration indicates the presence of contaminants. Another oil contamination signal is the odor. contaminated oils may have acidic characteristics.
