http://i46.photobucket.com/albums/f1.../referFlow.jpg
Dual tubes.. And, an
electronic expansion valve
http://ecorenovator.org/forum/applia...ion-valve.html
Since it uses a temperature sensor as feedback, maybe that electronic expansion valve will allow for using other refrigerants.?.
I've read R290 has good versatility in the type of lubes that can be used.
In the study, they flushed the unit out completely.
I think they didn't want any R410a lube in the system.
If I was going to do this, I would find some R290 compatible lube..