Maintenance and service must be performed by a qualified installer or service agency. At the beginning of each cooling season, the system should be checked as follows:
NOTE ‐ If insufficient cooling occurs, the unit should be gauged and refrigerant charge should be checked.
Cleaning of the outdoor unit's coil should be performed by a trained service technician. Contact your dealer and set up a schedule (preferably twice a year, but at least once a year) to inspect and service your outdoor unit. The following maintenance may be performed by the homeowner.
The outdoor unit must be properly maintained to ensure its proper operation.
REPAIRING DAMAGED INSULATION
Areas of condensation on the cabinet surface are an indication that the insulation is in need of repair.
If the insulation in need of repair is otherwise in good condition, the insulation should be cut in an X pattern, peeled open, glued with an appropriate all-purpose glue and placed back against the cabinet surface, being careful to not overly compress the insulation so the insulation can retain its original thickness. If such repair is not possible, replace the insulation. If using foil‐faced insulation, any cut, tear, or separations in the insulation surface must be taped with a similar foil-faced tape.
Source: MaintainX (Community Member)