So I've read this section 608 book of the Clean Air Act and feel good about passing this thing almost flawlessly. One obstacle still remains.
This Dupont refrigerant numbering system does not make much sense to me.

How do you figure out what kind of refrigerant it is based on its chemical formulation.

This example is right from the book.


Number of F atoms = 2
Number of H atoms + 1 = 2
Number of C atoms - 1 = 0

"The refrigerant is designated HCFC-22. Since carbon has four bonds and the total of F and H = 3, there is on C1 atom."

So based on the above confusion CHC1F2 is R-22. I've seen a few of these questions on practice exams. If anyone could give some insight I would feel a little more comfortable with it. -Thanks