Need help with Dometic Duo Therm Air Conditioner

Thanks for the replies, looks like I have now learned to use my Air Conditioner! :S

92 degrees outside today, turned it on Medium cool earlier, set to about half on the 'cooler' knob. In about 30 minutes, I noticed the ice building on the lines and compressor. So I cranked the fan up to High cool, and lowered the 'cooler' knob a bit. Came back home almost 4 hours later, and there is NO ice on the lines or compressor, and the temp inside is holding at a very cool feeling 75.

Thanks to all.