Electrolux Side by Side Refrigerator, Service Manual

Page: 81 / 137

7 3
Section E
Products using R-134a refrigerant will generally have a longer capillary tube to
maintain a similar flow rate and some models will have a larger condenser to
reduce the discharge pressures and lower start-up sound transmission.
Miscibility Of R-134a And Ester Oil
A special synthetic oil known as Ester oil is used as a lubricant in refrigeration
systems operating on R-134a. Ester oils are produced from alcohols and fatty acid
and are available in several different variants. Ester oils have a pleasant aroma
reminiscent of fruit.
Ester oils generally include various types of additives for improving certain
properties such as viscosity, temperature sensitivity, etc. These additives are often
aggressive, and skin contact with Ester oils should therefore be avoided.
One of the most important requirements made on a refrigerant system is that the
oil mix with the refrigerant. Since mineral oil and ordinary synthetic oil DO NOT mix
with R-134a, Ester oil is used for lubrication. Ester oil dissolves in R-134a.
Ester oil is broken down by chlorine and cannot be used with R-12 (R-12 contains
chlorine) or any other compound containing chlorine. Therefore, R-134a
refrigeration systems have virtually no tolerance for chlorine molecules from CFC
refrigerants (R-134a is an HFC and contains no chlorine).
For example, hoses that were used for a refrigeration system operating on R-12
may contain small quantities of mineral oil which can block the capillary tube in a
system operating on R-134a. As little as one milligram may be sufficient to cause a
blockage. In addition, sealed system components that have been used with CFC
systems must not be used with R-134a systems. These components may contain
residual amounts of refrigerant and oil which could damage an R-134a system.
At the earliest stage of development work on R-134a, tests were carried out on a
different type of synthetic oil known as Poly-Alkaline Glycol (PAG). This oil is also
used in certain air conditioning systems for cars. PAG and Ester oil DO NOT mix
with one another. Service equipment used for R-134a / Ester oil must not come
into contact with PAG.
CAUTION
During R-134a service, it is extremely important to avoid using equipment that may
contain residual amounts of mineral oil, CFC’s or HCFC’s which could enter and
contaminate the sealed system.