Refrigerant Terminology

Please use the correct name or names when specifying refrigerants. The guidelines are listed below:

^ Freon --> is a registered trademark of DuPont, and should only be used if referring to DuPont R-12.

^ DuPont's trade name for R-134a (automotive use) is Suva-->Trans A/C.





^ When referring to refrigerants, the terms Freon-->and Suva--> should not be used as a general reference. The proper terms are R-12 and R-134a

Comments regarding refrigerants:

^ R-12 and R-134a are not compatible with each other and should never be mixed, even in the smallest amounts.

^ R-134a for automotive use has a special tank fitting size (1/2" - 16 ACME) which is compatible with automotive service equipment





^ When purchasing R-134a, be certain that the fitting size on the tank is 1/2" - 16 ACME. This thread size is easy to recognize by the square thread, as shown.

^ Although R-134a has no ozone depletion potential (ODP), it does have a slight global warming potential (GWP). Due to this slight GWP, as well as its high cost, venting of R-134a into the air is not recommended.

^ Recovery/recycling of R-134a will be required by U.S. Federal Law, Clean Air Act Amendments of 1990.





Comments regarding PAG refrigerant oils:

^ PAG oil absorbs moisture from the air at an exceptionally fast rate, and moisture can damage the A/C system.





^ The graph on the following page shows that PAG oil left open to air (e.g. in an unsealed container) will absorb 2% moisture (by weight) in 120 hours (5 days).

^ PAG containers, and any A/C component which contains PAG oil (such as the compressor) should remain tightly capped and sealed until ready for use.

^ If you believe that a container of PAG oil may not have been adequately re-sealed after opening, dispose of the oil properly and use oil from a new sealed container.

^ When installing or servicing an A/C system, the refrigerant tube and hose connections should be sealed (all connections made and tightened to specification) without delay.

^ The above precautions will keep the absorption of moisture into the system to a minimum. Using moisture saturated PAG oil in R-134a systems may lead to the formation of acids and related system damage or failure.

^ Do not allow refrigerant oil (Nissan A/C System Oil Type S) to contact styrofoam, as the lubricant will damage this material.





Comments regarding condensers:

^ The parallel flow condenser can be identified by the refrigerant end tanks, and smaller, more closely spaced center section tubes.





Comments regarding liquid tanks:

^ For R-134a, the sight glass has been deleted. Refer to the service procedures section of this bulletin for additional information regarding the refrigerant charge determination. Pressure switches are not interchangeable between R-12 and R-134a systems.

















Comments regarding tubes and hoses:

^ Some R-134a tubes and hoses have reversed male/female connections to prevent interchangeability with R-12 components.