Liquid line sweating near the dryer is most likely caused by:

• A. Debris from the burned out compressor has clogged the dryer
• B. Overcharge of refrigerant
• C. Inadequate condensate drain
• D. Dirty condenser fins

Answer: (A)

Liquid line sweating happens when the surface of the pipe becomes colder than the surrounding air’s dew point, so moisture in the air condenses on it. If debris from a burned-out compressor clogs the dryer, it can create a restriction in the liquid line. That restriction can cause the liquid refrigerant to flash or severely throttled flow, cooling the pipe near the dryer. When the line surface drops below the ambient dew point, moisture condenses on it, producing the seen sweating. The other issues would typically affect temperatures differently—for example, overcharging tends to raise head pressure and condensing temperatures, an inadequate condensate drain relates to moisture issues in the evaporator area rather than the liquid line, and dirty condenser fins generally keep the line warmer by hindering heat rejection.