Back to Training HVAC 101 0% Complete 0/0 Steps Remove Locking Refrigerant Caps 5 Inch Media Filter Replacement Ladders, Drops & Attic Access Heating Sequence Of Operation - Standard Furnace Duct Inspection Drawing A System Finding Signs Of Rats In The Attic Space Insulation Check Dampers Explained HVAC 101 Remove Locking Refrigerant Caps Video 1 of 9 In Progress Next→ Remove Locking Refrigerant Caps These caps help prevent leaks and require a special HVAC key to access.