When purging a refrigeration gage manifold using system pressure as the source of refrigerant for purging, which of the fittings listed is normally tightened LAST?

Correct Answer: Option B — the low pressure hose fitting at the suction service valve service port

Purging gauge manifolds with system refrigerant involves cracking the low-pressure service port fitting last to sweep non-condensables and air out of the hoses safely.