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"Servicing The World With Automotive Air Conditioning Theory and Diagnosis"
-Automotive Air Condition Is Our Only Business-
BASIC R12 TO R134a Conversion
| RECOVER ANY R12 IN THE SYSTEM | Remove all R12 refrigerant using approved recovery equipment. When complete, the system must hold a vacuum for 5 minutes. if the system shows a positive pressure after 5 minutes, repeat the recovery process. |
| REMOVE THE R12 MINERAL OIL* | It is recommended that R12 mineral oil be removed from the system being retrofitted. This can be accomplished by draining individual components or by approved flushing systems. |
| REPLACE THE ACCUMULATOR OR RECEIVER-DRIER | Remove the used accumulator or receiver-drier and install a new replacement unit that contains desiccant designed for R134a systems. |
| PERFORM SYSTEM REPAIRS | Make necessary system repairs. check the condition of expansion valve, orifice tube and pressure switches. If bad, replace now, Check engine cooling system performance (Radiator, fan and shroud). |
| INSTALL AN IN-LINE FILTER | If the compressor is replaced, installation of an in-line filter on accumulator type systems is required to protect the compressor . |
| HIGH PRESSURE CUT-OFF SWITCH | Installation of a high pressure cut-off switch may be necessary on some vehicles to insure compressor durability. |
| INSTALL R-134a SERVICE PORT FITTINGS | Installation
of R134a service port fittings is required by law.
 |
| APPLY R134a LABEL | Complete retrofit label and affix in a prominent position in the engine compartment. This is required by law. |
| ADD R134a LUBRICANT | Add the correct amount of A/C lubricant for the particular system that is being retrofitted. |
| EVACUATE THE SYSTEM* | Evacuate the system for 45 to 60 minutes. |
| CHARGE WITH R134a* | Determine the correct charge for the system being upgraded to R134a use. In most cases, the R134a charge will be 10% less than the R12 charge. |
| PERFORM LEAK TEST | Leak test the system using equipment that will detect R134a refrigerant. |
| ROAD TEST THE VEHICLE | A 3-5 degree Fahrenheit increase in duct outlet temperature is not unusual. Adjusting the clutch cycling switch to reduce the cutoff pressure by 2 pounds (maximum recommended adjustment) or the installation of an auxiliary condenser fan may be necessary to reduce the duct temperature on some vehicles. |
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