Abstract: A portable, refrigerant recovery unit for transferring refrigerant from a refrigeration system to a storage tank. The recovery unit includes two, opposed piston heads rigidly attached to respective piston rods that extend along a common fixed axis. The piston rods are rigidly attached to the yoke member of a scotch yoke arrangement. In operation, incoming refrigerant from the system is simultaneously and continuously directed to the opposing piston heads wherein the forces of the pressurized refrigerant on them counterbalance or neutralize one another. The recovery unit also has a cooling fan driven by the motor for driving the scotch yoke in which the fan is driven through a step up gearing arrangement. In operation, the drive shaft of the motor is rotated at a first rate and the driven shaft of the fan is driven at a greater rate (e.g., twice the first rate) by the step up gearing arrangement.