Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Filling AC Refrigerant without Air Tagged: AC, refrigerant This topic has 1 reply, 2 voices, and was last updated 4 years, 2 months ago by Richard Kirshy. Creator Topic September 28, 2020 at 3:20 pm #963907 Aaron BParticipant When you fill refrigerant using a manifold gauge set to your automotive AC system, aren’t you also introducing the existing air from the manifold gauge hoses? This topic was modified 4 years, 2 months ago by Aaron B. Creator Topic Viewing 1 replies (of 1 total) Author Replies September 28, 2020 at 6:27 pm #963913 Richard KirshyParticipant Which is why you purge the yellow line with refrigerant prior to filling the evacuated system Author Replies Viewing 1 replies (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In