Pancake models are designated with a “P” as the first letter of serial number. They are made with 1/20- to 1/3-hp motors. All of them use an oil charge of 22 oz and R-134a or the latest replacement as a refrigerant. They have a temperature range of 20 to 55°F (−6 to 13°C). The smaller horsepower models are used where −30 to 10°F (−34 to −12°C) is required.