R-Pro › Field cases › Air conditioning
External Condensation on Drain Line — Insufficient Insulation
Likely causes
Missing or damaged insulation — condensation looks like ceiling leak
Check: Touch line to find cold spots with water droplets. Insulation partially stripped or too thin. More frequent in high humidity (summer, monsoon, restaurant kitchens). Distinguished from leak: leak has steady flow, condensation has scattered drops along line surface.
What to do: 1) Replace damaged insulation with new (high-density foam like Armaflex). 2) Thickness should be ≥50% of line diameter — 9mm line needs 9mm+ insulation. 3) Insulate all joints and bends — gaps cause condensation. 4) Seal insulation ends with self-adhesive tape — prevents loosening over time.
Confusing refrigerant line (suction) with drain line — wrong-line diagnosis
Check: Suction line (low-side copper, ¼"–5/8" diameter) also condensates — looks identical to drain condensation. Touch: very cold (0–5°C) = suction; lukewarm (15–25°C) = drain. Suction line sweat is insufficient insulation or normal operation.
What to do: 1) For suction line condensation, reinforce suction insulation — separate from drain insulation. 2) Don't bundle suction and drain into one insulation; insulate each — surface temps differ. 3) Diagnose line identity precisely before action. 4) When two lines are close, leave ≥5 cm gap between them.
Condensation looks like a leak and is often misdiagnosed. Standard diagnosis: touch line for temperature → identify source line → check insulation. Good insulation alone solves 99% of cases.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
Open R-Pro →