I mean dual stage as in each compressor as a stage.
I guess I will call it dual phase
The reason adding R134a should help,is because Propane is lighter than R12.So R134a should make it a bit more heavy.I think,I dont have charts for it,but I remember that someone used propane and it didnt even cool with propane until he added R134a....

Now my system has 2 compressors for the main waterchiller.
Then a seperate system cooling the condenser.

The system cooling the condensor is also going to be dual staged.

I dont know if I am going to add R134a or not....
R22 works alot better than R290,but I ran out.But since the r290 is going well below -60F I guess it is working ok....

Low side psi is around 16-20 inches and high side with new smaller cap is about 75psi I think.With the old bigger capillary I got about 5-10psi high side....
Those are probably a little off..
My cascade cooler has a leak so it isnt stable.

Something is stumping me right now,what are the pipes coming out of the compressor?Steel or something?
Silflo will not stick to it,and brass melts at too high of a temp and burns a hole in my copper.