Why is it important to not exceed the maximum fill percentage when transferring refrigerants?

When transferring refrigerants, it is critical to adhere to the maximum fill percentage primarily to accommodate pressure changes that occur due to temperature variations. Refrigerants are liquids that can change into gases when heated, and if a cylinder is filled beyond its recommended capacity, there may not be enough space for the vapor that develops as the temperature increases. This can lead to excessive pressure inside the cylinder, potentially causing leaks, ruptures, or even explosions due to increased pressure. Allowing for these pressure changes ensures the safety and integrity of the storage container and minimizes the risk of dangerous situations.

Though other factors like cylinder damage and efficient refrigerant flow are important considerations, the safety of managing pressure effectively remains the foremost reason for maintaining the proper fill percentage.