What is the procedure for retrofitting an older R12 system to the new R134a refrigerant?
Perform the repair exactly as you would if the refrigerant were R12. Only, instead of using a mineral oil to lubricate the system use an approved ester oil. Be sure to flush the system completely in order to remove as much of the residual, mineral oil as possible. Make sure flushing methods are EPA approved. Evacuate the system for a minimum of 45 minutes and begin charging with R134a refrigerant. Start with 70 percent of the charge you would use if charging with R12. Under some conditions, auxiliary condenser cooling fans may be required or you may need to replace the condenser with an approved serpentine type. Also, be sure to use the new style o-rings when replacing components. (There are many new “drop-in” replacement refrigerants currently being tested. We will keep you posted on their development.
