Cassette Leaking After Heavy Rain: Drain Outlet Froze Briefly
Aircon case in Marina Bay, Singapore: water leakage traced to drain outlet freezing momentarily when cold air stream hits it during peak condensate load after targeted diagnosis checks.
Case Details
| Unit | LGCassette |
|---|---|
| Age | 4 years old |
| Location | CondoMarina Bay, Singapore |
| Reported | Water dripping from the corner of the ceiling unit during last week's heavy rain. Stopped when the rain let up. Concern was whether it would recur during the next storm and whether the drain was clogged. |
What We Checked
- Drain line itself was clear — no blockage.
- Drain outlet was positioned directly below the cassette in the cold air discharge path.
- During the diagnosis visit on a humid day, frost visibly formed at the outlet.
- Frost formation coincided with peak condensate production from the indoor coil.
The Diagnosis
During heavy rain with high indoor humidity, the coil produces heavy condensate — and because the drain outlet sits in the cold air stream, it freezes briefly when flow peaks. The blockage lasts only minutes, but during continuous rain that is enough for backup to overflow the pan and drip from the edge.
What Fixed It
The drain line and pan are fine — the problem is the outlet position. Moving it away from the cold air path gives condensate a warmer flow path, and the repositioning is straightforward.
The drain outlet was repositioned away from the direct cold air stream. During the next heavy rain two weeks later, no leaks occurred. The unit has remained dry through subsequent rainy periods without any further drainage issues.
Why This Happens
Drain freezing is rare but specific to unit placement and humidity extremes.
- A drain outlet sitting in the cold air stream freezes briefly during heavy condensate loads — blocking flow for just a few minutes, but during heavy rain that is enough to cause overflow.
- Moving the outlet away from the cold air path prevents freezing without affecting normal drainage.
Related Reading
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