Older condo leaked after servicing: drain insulation left open in trunking

Daikin Wall-mounted·9 years old·Condo·Marine Parade, Singapore

Water appeared along the bedroom trunking the day after servicing. The aircon still cooled and there was no water spilling from the front of the unit.

We checked whether the indoor tray was overflowing. It was not. The water was forming inside the trunking near an exposed cold section. The timing after service told us to inspect disturbed insulation and covers. The coastal humidity made condensation more plausible because any exposed cold section inside trunking can sweat quickly. We left the unit running while the trunking was open, so we could see whether water came from the drain path or formed on the outside surface.

A cold section of the drain route was exposed inside humid trunking. Moisture condensed on that exposed area and collected until it dripped out of the trunking. The open insulation created a cold spot inside an enclosed, humid space. Moisture in the trunking air condensed on that surface, then collected and dripped out as if the drain had overflowed. The water was real, but it was forming outside the drain path rather than leaking from inside it. That distinction mattered because the drain tray could pass water normally, so repeated flushing would not stop the sweating at the exposed cold section. Once the insulation gap was visible, the leak timing after service made sense.

We dried the trunking, rewrapped the exposed section, and confirmed the drain tray still flowed properly. No chemical wash or pipe replacement was needed. We corrected the insulation first, then ran the unit long enough to check both drainage and sweating. That separated the fix from a simple flush and avoided recommending chemical wash for a problem it would not solve. This was important because a drain flush can look successful while the cold exposed section continues to sweat after the technician leaves.