From inside (document excerpt):
24APA5 Performancet 15 Series Air Conditioner with Puronr Refrigerant 1 1/2 to 5 Nominal Tons (Size 18 60) Product Data INDUSTRY LEADING FEATURES / BENEFITS Energy Efficiency S 13.5 — 16.5 SEER/11.7–13.5 EER New Aesthetic Design S WeatherArmor Ultrat Baked- powder paint -on Steel louver coil guard Color matched cabinet screws Extra Quiet Operation S Silencer System IIt for sound as low as 66 dBA Quiet mount split post compressor grommets Exclusive Silencer top design Forward-swept condenser fan blade Compressor sound hood Laminated compressor mounting plate the environmentally sound refrigerant Carrier’s Air Conditioners with Puronr refrigerant provide a collection of features unmatched by any other family of equipment.
The 24APA5 has been designed utilizing Carrier’s Puron refrigerant. The environmentally sound refrigerant allows you to make a responsible decision in the protection of the earth’s ozone layer. As an Energy Starr Partner, Carrier Corporation has determined that this product meets the Energy Starr guidelines for energy efficiency. Refer to the combination ratings in the Product Data for system combinations that meet Energy Starr guidelines. Reliability, Quality and Toughness S Scroll compressor S Field–installed 16 cu. in. filter drier S 8–pole PSC ball–bearing condenser fan motor S Back–seating service valves S High–pressure switch S Low–pressure switch S Internal pressure relief valve S Internal thermal overload Controls and Diagnostics S Infinityt Control compatible S Standard thermostat control with 3–wire or 2–wire 24v connection to outdoor unit. (2-wire cpability starts with serial number 3006) S Utility Interface Connection S Up to 14 point diagnostic capability Applications S Longline — up to 250 ft. total equivalent length S Low–ambient operation (down to 0_F) with complete Infinityt System and crankcase heater S Low-ambient operation (down to 0_F) with standard thermostat and additional accessories (see Accessory Usage Guideline in this document).