How To Convert R12 To R134a: Conversion Chart & Formula

Convert R-12 to R-134a

If you have an older car (Pre-1994) and your car air conditioning has an R-12 refrigerant system. Which works fine, has no leaks, contains a normal amount of refrigerant, and the system cools properly. So, you do not need to change the AC system to R-134a.

However, If your car AC has a problem then you have to change the system to the R134a system. Because refrigerant R-12 is banned and is not available in the market. Luckily, you are on the right page to convert the R12 to the R134a system.

In this powerful guide, you will learn how to convert R12 to R134a system with seven quick steps, a conversion chart, and a conversion formula.

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How To Convert R-12 To R-134a System

AC Refrigerant Conversion
AC Refrigerant Conversion

R-12 refrigerant was common in the past. Now it is banned due to global warming. Conversely, now the R-134a is common in the automotive industry. Before 1994, R-12 refrigerant was mostly used in automotive AC systems. It was considered a perfect refrigerant until discovered that it causes ozone depletion.

In 1995, the Society of Automotive Engineers (SAE) changed the standard for refrigerants and made R-134a a new standard. Recently, the automotive industry is moving to another refrigerant called R-1234yf. This has very low global warming potential compared to any other refrigerant.

Now come to the point, you can convert/retrofit the system in two ways. One way is to change every part of the old system and retrofit new parts like the condenser, evaporator, compressor, and hose pipes. This is called the Factory Method and manufacturers recommend this method. But, the problem is, it is a very expensive method.

The second way to retrofit R12 to R134a is the modification of existing parts. Only a few changes need to make in the system, such as pressure ports, receiver drier, and pressure switches compatible with R-134a. Now below are some practical steps to convert R-12 to R-134a system.

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7 Quick Steps To Convert R12 To R134a

Here are the quick steps to replace the R12 with the R134a system.

1. Discharge The R-12 Refrigerant:

Discharging The Refrigerant
Discharging The Refrigerant
  • Empty the system from the old R-12 refrigerant.
  • Recover the R-12 refrigerant for recycling.

2. Flush The Whole System:

  • Remove all the oil and contamination.
  • Flush the entire system from mineral oil and debris without leaving any sign of R-12.
  • Flush AC pressure lines.

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3. Retrofit The R-134a System Parts:

  • Retrofit the R-134a system parts, especially the receiver drier and pressure ports.
  • Because the R-134a system needs a larger size receiver drier and different ports for filling the refrigerant.

4. Evacuate The System:

Evacuating The AC System
Evacuating The AC System
  • Attach the vacuum gauge and empty the system of air and moisture.
  • Hold the vacuum for at least 45 minutes.
  • Check for leaks.

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5. Charge The System:

Charging AC System
Charging AC System
  • First of all, put the proper amount of Ester lubricating oil.
  • Then, fill with R-134a refrigerant until you get the desired cooling.
  • If you don’t know how much refrigerant to put in, you can figure out the exact amount of refrigerant by the formula mentioned below, or you can also take help from the below chart.

6. Install The Port Caps

Checking AC Leak
Checking AC Leak
  • Install the port cap and look.
  • It is better to do a road test.

7. Attach The Warning Labels:

R-134a Warning Label
R-134a Warning Label
  • Attach the retrofit warning label of R-134a to warn the technician for future service.

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R-12 To R-134a Refrigerant Conversion Formula

R134a is lighter than R12, which means the same volume of R134a is lighter than the same volume of R12. So, it is important to know how much r134a refrigerant is to be installed while converting from R12 to R134a system. To exactly know how much refrigerant to install, you need to know the formula.

First know how much r12 refrigerant does consume your system, multiply it by 0.9 then subtract by 0.25 to get the desired value.

Formula: (R12 Refrigerant Specification x 0.9) – 0.25 = R134a Amount Of Refrigerant

R-12 To R-134a Refrigerant Conversion Chart

R-12 To R-134a Refrigerant Conversion Formula (Source ricksfreeautorepairadvice)
R-12 To R-134a Refrigerant Conversion Formula (Source ricksfreeautorepairadvice)

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