Komatsu PC78US-6 Operation & Maintenance Manual page 245

MAINTENANCE
CLEAN INTERNAL AND EXTERNAL AIR FILTERS OF AIR CONDITIONER
If compressed air is used, there is danger that dirt may fly and cause personal injury.
Always wear safety glasses, dust mask, and other protective equipment.
NOTICE
The guide for cleaning the filter is 500 hours, but if the machine is used on an extremely dusty jobsite, reduce the maintenance
interval and clean the filter more frequently.
When washing the floor, be careful not to get water on the air conditioner system.
REMARK
MAINTENANCE PROCEDURE
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