Assess the causeFollow the evidence.
Inspect filters, blower condition, air-path obstruction, fan speed control and signs of icing.
The exact model and operating conditions determine which tests apply. These are possible inspection directions, not a list of components that must be changed.
Before the appointmentKeep the useful details.
Explain whether the airflow is weak at every fan setting and whether it gets worse over time.
Record the timing, previous work and accessible model label. Do not remove covers or handle live, refrigerant or pressurised components to obtain information.