I have a pressure/temperature chart of different refrigerants but my question is, in a refrigeration unit (ice maker) charged with R-12, what is the working pressure of it and where would I find this info in the future?

At 32 pounds R 12 will be 30 F That is a good point for running an automobile.

At 9.1 pounds it will be 0 F degrees.

At -21 pounds that is the boiling point of Freon R 12.

I am not sure that ths is what you want.

Pressures are not enough. You need to learn about superheat and subcooling.

Start here:

Charge by sub cooling? - HVAC-Talk: Heating, Air & Refrigeration Discussion (http://hvac-talk.com/vbb/showthread.php?threadid=69960)

At 32 pounds R 12 will be 30 F That is a good point for running an automobile.

At 9.1 pounds it will be 0 F degrees.

At -21 pounds that is the boiling point of Freon R 12.

I am not sure that ths is what you want.


I think what I was looking for is the PSI low side and high side when a system is properly charged without the superheat/subcooling calculation. Like the other answer I received, I need to be refreshed on superheat and subcooling if I want to be precise on my charge.
Thanks for the help though.

Pressures are not enough. You need to learn about superheat and subcooling.

Start here:

Charge by sub cooling? - HVAC-Talk: Heating, Air & Refrigeration Discussion (http://hvac-talk.com/vbb/showthread.php?threadid=69960)

I know I need to refresh myself on superheat and subcooling. Thanks for the help.

How many pressure work for R12