In commercial refrigeration coolers, the fans are supposed to run continuously. The evaporator temperature in a 35F cooler is 25F and being below freezing will accumulate frost. When the thermostat is satisfied the unit pumps down, and shuts the compressor off, but with the fans continuing to run. The 35 degree air blowing across the evap coils defrosts them, and is called "off cycle defrost system". Freezers shut the fans off for the defrost cycle usually using electric elements to melt the ice/frost. The fans are off to keep from blowing the heat around the freezer and blowing water droplets on the floor to freeze and make an ice skating rink. Like earlier mentioned oversized equipment doesn't allow for long enough run times to completely remove the humidity from the air. Hot gas bypass systems can be costly and dangerous to compressors if not set up correctly, and are big energy wasters as the compressor running at full amp draw, but you are bypassing hot gas to the evaporator to keep the suction temp up and reducing system capacity. In the long run you are better off to get correctly sized equipment, and sell off the oversized stuff. I do commercial refrigeration load calculations, and equipment selections, for a living and can help you out with the sizing if you get me some basic information. E-mail me Skeeters65 and I can figure it out for you.