A pressure test is carried out to confirm the efficiency of the air conditioning system and whether any refrigerant is still present. No appointment is necessary for this test; it is a "drop-in", "while you wait" service and takes approximately 10 minutes. A re-charge includes the following operations:- Recovery/removal of old refrigerant. System evacuation. This process will clean and remove particles and moisture from the system to enable correct operation once re-charged. Add compressor oil as necessary.