A valve sub-assembly on a pneumatic conveyor factory fails. The air system has to be shut down, locked out, & zero energy state. What is the procedure?
A. Remove old valve, check bearing, install new valve while maintaining minimal clearance between vane & drum
B. Remove old valve, check bearing, install new valve while advancing 1/2 inch between vane & drum
C. Check air pressure, remove old valve, then install new valve while maintaining 1/2-inch clearance between vane & drum
D. Remove old valve, install new valve, then bearing while maintaining 1/4-inch clearance between vane & drum