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R-12 Change Out

Refrigerant 409A - Change Out of R-12

On November 15, 1990 President Bush signed the 1990 Clean Air Act Amendments setting our National Policy for the reduction and elimination of ozone depleting substances including CFC's. Bush ordered the phase-out of the production of CFC's for December 31, 1995. It was believed that no direct replacement would be available for R-12, a very popular CFC refrigerant, and, a lengthy procedure would be necessary to change out R-12 to a lesser ozone-depleting refrigerant.

 

In about 1999, ELF atochem produced an interim blend called R-409A. This refrigerant is a "drop-in replacement" for R-12 and replaces R-12 with little modification to the original system. However, as an interim replacement HCFC, R-409A will be banned in the future. The following tips will help the technician who is going to try this change-out. The tips will help to make the change-out easier.

 

Refrigerant Retrofit Procedure: R-12 to Forane 409A

 

1. Get baseline data from the existing system. These data include:

 

  • Suction line temperature
  • Discharge line temperature
  • Box or product temperature
  • Suction pressure
  • Discharge pressure
  • Superheat
  • Subcooling
  • Quantity of R-12
  • Amperage of compressor
  • Coil discharge temperatures

 

2. Recover existing R-12

 

3. Leak check and change drier(s)

 

4. Evacuate the system to at least 500 Microns.

 

5. Charge the system with liquid phase R-409A to approximately 85-90% of the original R-12 charge quantity.

 

6. Repeat the baseline data from step 1. Use an R-409A pressure/temperature chart to check results.

 

7. R-409A has normal operating pressures of 1-2 PSI higher on the low side and 20% higher pressure on the high side of the system. Adjust expansion valve if necessary.

 

8. If a leak should occur remember that blend fractionation could result in one component of the refrigerant mix to leak at a faster rate than the other parts. The best way to add needed refrigerant is to recover the remaining refrigerant and weigh in a new charge.

 

9. Remember to tag the unit with the new refrigerant identification and quantity in a visible location.

 

For more information contact our Branch Office nearest you.