I wrote Friedrich asking how to determine (by model number) which of their legacy window units use R22 / R410 respectively and this was the reply.
I though it might be useful to some;
"As with all manufacturers, Friedrich began using the new R410A refrigerant in all units produced effective January 1, 2010. You can tell from the model number in our window units which have the R410A. Looking at a regular model number such as SS08L10 which is a Quietmaster Programmable unit. The 5th digit (the L) indicates a unit that was manufactured prior to 2010. If this 5th digit is an L or earlier (J, H) then the unit has the R22 refrigerant. If the 5th digit is an M or an N that will indicate that it was manufactured in
2010 or later and has the R410A refrigerant. This is on the Friedrich made units (models starting with XQ, SS, SM, SL, RS, KS, YS, YM, YL, EQ, ES, EM and EL).We also have window units that start with the letters CP. On these units if the 5th digit is an E, N or C then the unit has the R22 refrigerant. If the 5th digit is an F or a G, then that unit has the R410A refrigerant. Of course, there is always that one exception. If you have the model CP05N10 then you would have to know the serial number to determine the type of refrigerant used.
If all else fails, the data tag located on the unit will also state which type of refrigerant is used in the unit.
Thank you for contacting Friedrich."