Final answer:
The liquid line filter drier should be replaced when it becomes completely clogged, as part of regular maintenance. This ensures efficient system operation and prevents biofilm growth.
Step-by-step explanation:
A liquid line filter drier should be replaced when it becomes completely clogged and causes system issues. Central heaters and air conditioners have filters that are vital for trapping dust and other pollutants. These filters require regular replacement or cleaning to ensure the system operates efficiently. As part of a routine maintenance program, it is essential to monitor the condition of the filter drier, rather than wait for visible corrosion or system relocation. This preventive approach helps to safeguard against the growth of biofilms within the system and ensures the proper functioning of the cooling and heating components.