Thanks again for your comments and interest. I do not have the model number now.
We had someone come in and charge both refrigerants. A day later the unit stopped working again. They then charged one side with nitrogen and it leaked into the other side.
So we concluded it was a leak in the cascade condenser. They came in and removed the refrigerants and we have been planning to have them come back to do the repair, but they have not had the time. Money has been a little tight so we have been looking for someone who uses the R508, so we do not have to pay for the full 5 lbs minimum purchase. As far as what we have been planning to do in-house, we have been thinking we can change the cascade condenser and then have someone come in and re-charge the system.