There's simply no compressed air dryer in the system. The air leaving the aftercooler is at 100% relative humidity, any further cooling in the piping dumps water.
What you'll see
Confirm there is genuinely no dryer. Some systems have a dryer installed but bypassed -- check the valve positions.
How to diagnose
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Trace the air path
Follow the compressed air from the compressor outlet through the system. Is there a dryer anywhere in the path? Some are integrated into the compressor (FF models on Atlas Copco). Some are separate standalone units. If there's nothing between the compressor and the distribution piping except maybe a receiver, you don't have a dryer.
Result: No dryer found = install one.
How to fix it
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Install a refrigerant dryer
For most industrial applications, a refrigerant dryer achieving 3 degrees C pressure dewpoint is sufficient. Size it for your compressor's output capacity. Also install a proper condensate drain after the dryer. The difference is dramatic -- from 3+ liters/day of water in the lines to near zero.
Don't rely on the aftercooler alone to prevent water problems. The aftercooler removes the bulk of the moisture but the air leaving it is still saturated. Any further cooling in the piping will produce condensate. A dryer is not optional for most industrial applications.
Refrigerant compressed air dryer (sized to match compressor capacity). Auto drain for dryer condensate. Piping for installation.