... safe operating; 3) Compact structure design Medium and high temperature Air cooler 1. Applied room temperature: -5°c~+20°c2. Refrigerant: R22 ... , R507a3. Standard Equipment: Compressor, crankcase heater, oil pressure safety switch, air-cooled condenser, receiving tank, drier-filter, meter panel, pressure controller ... 2 refrigeration oil, protection gas, double stage compressor with intermediate cooler