Distinguish airflow problems from cooling faults
If the system runs but rooms remain warm, airflow, coil condition, and duct distribution are useful points of comparison. Weak airflow at several outlets differs from a restriction affecting one branch, and ductwork is relevant to central air rather than a ductless installation. A wet indoor-coil area also warrants investigation to determine where water is coming from. These observations guide diagnosis; they do not by themselves establish that refrigerant is low or that a coil needs replacement.
