Deep in thought on R134a

Given the following situation, leak checking an air-cooled chiller operating with 134a and one circuit is flat. Charge 5-8 lbs of 134a bring system pressure up to approx 25 psig. Topoff with nitrogen to 200 psig. Evaporator temp is 52 deg F and outside air temp is 49 deg F. Since the 134a was already superheated, and raising the vapor condensing pressure to 200 psig which corelates to 130 deg F for 134a, wouldn't the 134a condense on the colder surfaces rendering the trace charge unusable??????? Have been looking at Dalton's Law, but still do not have a clear understanding. Any articles, publications would be greatly appreciated. Unless one of you fine people could clearify this for me! Remember....this is only a theory....

The pressure may equate to 130°F but I very much doubt if your system temperature rose as you added the nitrogen.

By the way is this worth pursuing in light of the illegal activity involved? :D

That is my point exactly. The system temperature stayed at 50 deg F. That is why I am saying the 134a should condense due to the vapor temp and pressure.

The way I understand Daltons law is that if you just have refrigerant vapour in your system then adding nitrogen will not make the refrigerant condense. The law states the the gases will act as if they occupied the space on their own. The refrigerant wont condense because there are too many nitrogen atoms in the way so the refrigerant molecules can't link and form a liquid.
Therefore the R134a wont condense mearly by adding nitrogen. The only way to get it to condense is to reduce the volume of the system (not likely) or add more mass of refrigerant until you get the system pressure to reach the saturated temp/pressure for the system temperature.
I suppose theoretically reducing the ambient around the system enough (a lot for your example with 5-8lbs in) would cause the refrigerant to condense.

I think my theory is sound. Watch this space!

Andy.

Thanks Tayters, in your discription I picked up on something that sparked a vision of what is taking place inside. The refrigeration circuit is for all practical purposes a single shell (albeit overlooking the piping) and as such, the two gases do occupy the same space. Their molecules are intermixed among each other. Here is a link to describe the gases with images. I now fully understand and thanks Tayters for jarring MY brain molecules!!!!!!!!!!

http://www.ausetute.com.au/partialp.html

Also here are some images from same website.