Installing your Advent Air RV Air Conditioner - 13,500 Btu - White # ACM135 backwards could result in damage to the unit. Air going the reverse way would blow through the condenser vents backwards trapping dirt and debris in them instead of pushing it out and would cause the fan to rotate backwards. AC units are meant to only go one way so I do not recommend placing it backwards on your 2019 Coachmen Clipper Express Camper view full answer...