[ossiblue]

Originally Posted by speeder

Why do you need to warm the freon can?

Simplified, it's the same reason why the AC cools your car. Freon in the can is under pressure and in a liquid state. The rapid discharge of the liquid through the hose to the AC allows the pressurized liquid to expand and become a gas--it's natural state. That conversion from liquid to gas draws heat from its surroundings resulting in a cooling of anything in the immediate area--like the can or the coils in the AC. If the can is not kept from freezing, the expansion of fluid to gas within the can may slow or stop. The process in the AC system is regulated by expansion valves to keep the cooling process stable and prevent freezing of the components.