Why is it necessary to crack and close the valve on the tank before attaching the regulator?

Cracking and closing the valve on the tank before attaching the regulator is primarily necessary to expel foreign matter. When the valve on a gas tank is opened for the first time, there may be dust, debris, or other contaminants that could be present at the opening of the valve or within the tank itself. By cracking the valve, you allow a small amount of gas to escape, which helps to blow out any particles that could interfere with the proper functioning of the regulator or potentially cause leaks.

This step is crucial for ensuring that the regulator is functioning safely and efficiently. If any foreign matter were to enter the regulator system, it could lead to malfunctions or hazardous situations. Therefore, expelling any contaminants and ensuring clean connections is an important safety measure in the handling of pressurized gases in the StarGuard system.