My independent M/B mechanic recommends starting that A/C system once a month. It keeps the many seals lubed, which aid in preventing leaks. Compressors are pretty tuff machines, so when the system starts blowing hot air, low OR no Freon because of a leak somewhere is usually the culprit. I don't know about the XFire compressor, but some others will NOT even engage with no or low Freon - to prevent possible resulting damage. I agree pretty much with Pizzguy - lower temp first BEFORE turning down the blower. I've known that most of my life!