Aircon New Unit Leak, Drain Pan Unseated

Case Details

What We Checked

• Water dripping from the front edge of the indoor unit, not from the drain outlet.
• Drain pipe was clear and flowing normally when tested.
• Drain pan was shifted slightly forward from the evaporator coil housing.
• A visible gap between the pan edge and the housing allowed condensate to bypass the drain path.

The Diagnosis

During the previous service, the drain pan was removed for cleaning — a standard step in general servicing. When it was put back, it was seated a few millimetres forward of its correct position on the guide rails. That gap meant condensate forming on the evaporator coil surface rolled down the fins, reached the bottom edge, and dripped past the pan into the unit housing rather than collecting in the pan and flowing to the drain outlet. The drip rate increased as the unit ran longer because condensate volume rises with continuous cooling. The unit itself was functioning perfectly — the water was simply missing its collection path.

What Fixed It

We slid the drain pan back into its correct position on the guide rails, pressing it flush against the evaporator coil housing until the clips engaged. We then ran a full cooling cycle for thirty minutes, watching the condensate path the entire time to confirm water was reaching the drain outlet without any bypass dripping. A pour test with additional water onto the coil surface confirmed the path was intact under higher flow. No parts were needed, no warranty claim was required, and the unit continued operating normally.

The dripping stopped completely. The unit ran through a full cycle with all condensate reaching the drain outlet as designed.

Why This Happens

Post-service leaks on new units usually trace back to reassembly.

• Servicing requires removing the drain pan to flush out accumulated sludge. The pan sits on plastic clips or guide rails that hold it flush against the evaporator coil housing. If it goes back even a few millimetres forward, condensate rolling off the coil misses the pan and drips from the front of the unit.
• A leak that starts only after servicing — on a unit that was completely dry before — points to handling during that visit, not a manufacturing defect. The timing correlation is the strongest diagnostic clue.
• Checking drain pan alignment at the end of every service visit takes seconds. Run a brief cooling cycle, watch where condensate flows, and confirm it reaches the drain outlet before packing up. This single step prevents the pattern entirely.
• Ask your technician to run a water test after reassembly. A small pour of water onto the coil surface confirms the drain path is intact. If water drips from the front edge instead of flowing to the outlet, the pan is not seated correctly.