Greetings!
Thats my first post. sorry fo my bad english.

After making couple of simple phase-change systems, i finally decided to go cascade.
Parts:
2 Aspera compressors- 2178Gk and 2168GK
P404a for the first stage and R23 for the second
Lytron LL520 heat exchanger ( http://www.lytron.com/standard/he_liquid_drawings.htm )





When i started building this cascade i didn't know what freons
will be used, so first i tested it with R404a on the first stage and
R410 on the second.



Then i got R23 in the second stage and sinse then i've been having problems with load.
Without loading it looks so :



My main problem seems to be the capillary tube in the second stage.
I think i shoud cut some of the lenth. My goal is to get this cascade stable at 220-230W...Certainly I shall pick up by practical consideration length of cappilary tube, but on it many time and work will leave.
I would be very greatful if someone could help me with it...