and charging the system. Although R-12 is considered the safest refrigerant for automotive air-conditioning systems, the containers are under considerable pressure at ordinary temperatures. To prevent accidents or damage to the system, you must observe the following precautions:

Do not subject the containers to excessive heat and do not store them in direct sunlight or near a shop heater.

Use hot water (fig. 13-2) or rags saturated with water at temperatures not to exceed 125°F when refrigerant containers must be warmed for system charges.

Never use a direct flame or a heater to warm containers or cans.

Figure 13-2. - Warming the refrigerant by using hot water.

Do not subject refrigerant containers to rough handling.

Do not drop or strike containers.

Keep refrigerant tanks upright, and be sure the metal cap is installed to protect the valve and safety plug when the tank is not in use.

Do not transport refrigerant tanks or cans in vehicle passenger compartments.

Cover the containers to protect them from direct sunlight when they are carried in an open truck.

When you dispense refrigerant from cans, use the specified can valve that has provisions for puncturing the can only after the valve is installed.