Older condo trunking drip: insulation gap on a cold pipe

Panasonic Wall-mounted·10 years old·Condo·Newton, Singapore

The bedroom cooled normally, but water marks appeared along a trunking run after overnight use. The owner had been told the drain might need replacement. There was no obvious drip from the indoor unit itself, only dampness along the covered pipe route.

We checked where the water started instead of assuming every trunking drip was a drain fault. The indoor tray, drain outlet, trunking route, and cold pipe insulation were inspected in order. The pattern mattered because the water appeared after long runtime, not immediately when the unit started.

The water was condensation from a cold pipe section inside the trunking. A gap in the insulation let humid room air reach the cold surface, so moisture formed and collected inside the cover. From outside, it looked like drain water because the mark followed the trunking. The drain path was not the main issue, which is why replacing the drain line would not have stopped the damp patch. The clue was that water started away from the unit casing and appeared only after the pipe had stayed cold.

We dried the area, corrected the insulation gap, and checked the drain path again before closing the trunking. The recommendation was a targeted insulation repair, not drain replacement. We also told the owner to watch whether future water appears only after long overnight cooling, because that timing is useful when separating condensation from active drain overflow. No gas work was needed because cooling was normal. The next service note should mention the repaired trunking section so the same spot can be checked first.