Minimum requirements for converting a system to R134a.

Information on some common auto air conditioning topics.
Archived Forum

Moderators: bohica2xo, Tim, Dougflas, JohnHere

User avatar
Site Admin
Posts: 603
Read the full article
Joined: Tue Apr 12, 2016 2:19 pm
Location: Scottsdale, Arizona

Minimum requirements for converting a system to R134a.

Post by Tim »

Minimum requirements for converting a system to R134a.

If the system has any refrigerant R12 left in the system it must be reclaimed by an approved recovery machine.

Accumulator/drier must be replaced with an R134a compatible replacement. Conversion fittings and labels must be added to the system. The label should have the amount of R134a used and quantity and oil type listed. If the vehicle is not equipped with a high pressure cut off switch it must be added.

That is the required minimum! Flushing the system to remove the mineral oil and debris should also be done. R134a and mineral oil do not work well together so leaving it in the system with R134a is not recommended! O-rings should be replaced with either NBR or HNBR replacements. Adjustment of the pressure cycling switch may also be needed to achieve the best performance. In some cases, an upgrade of the condenser may be required to achieve the original performance.

There are many different suggestions when charging an R12 system with R134a. The system must be evacuated before starting the charging procedure. I suggest you start with about 70 percent of the original R12 charge and add an ounce at a time until vent and pressure readings reach the best available results. Remember it is easy to overcharge a system with R134a so patience is important.
Please support for your Auto A/C Parts and Tool needs.

Help Support the Forum