I guess I am a little bit old school on stuff like this. I hate to keep fixing things over and over. IMHO If I have spots in the air line that are freezing up it is because I have "traps" or low points for the moisture to collect. Eliminate the low spots and provide a continuous grade on the air lines. To quote 10X "These lines go up and over the bank out to the diffusers." Cut the lines thru the bank to keep the downward grade and eliminate the "traps" to fix the problem instead of continually fighting it year after year?

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