Aircon Leak After Service, Drain Tray

Case Details

What We Checked

• Water was dripping from the front bottom edge of the indoor unit, not from the drain pipe.
• Drain tray was sitting slightly tilted and not flush against the evaporator housing.
• A visible gap between the tray edge and the housing allowed condensate to spill forward before reaching the drain outlet.
• After reseating the tray flush and running a water test, all water flowed through the drain outlet with no dripping.

The Diagnosis

The drain tray had been removed during the general service to allow cleaning access to the evaporator coil. When reassembled, the tray was not seated flush against the evaporator housing. A gap of several millimeters formed between the tray lip and the housing edge on the front side. During cooling, condensate formed on the coil fins and dripped down into the tray as normal, but instead of collecting and flowing toward the drain outlet, water reached the misaligned edge and spilled forward past the tray. The drip rate increased as humidity rose during the day. The evaporator coil itself was undamaged, and the drain pipe had no blockage.

What Fixed It

The evaporator coil was not cracked and no parts were damaged during the previous service. The drain tray simply was not seated back flush against the housing. We reseated the tray, verified that the lip sat evenly against the housing on all sides, and ran a controlled water flow test by pouring water directly into the tray. All water flowed cleanly through the drain outlet with no spillage at the edges. We then ran the unit through a full cooling cycle and confirmed that condensate collected and drained correctly under real operating conditions. No parts were replaced and no coil work was needed.

The drip stopped immediately after the drain tray was reseated flush. The unit ran through a full cooling cycle with no water escaping the drain path. No parts were replaced and no coil work was needed.

Why This Happens

Post-service leaks — why the drain tray is the first check.

• During a general service, the drain tray is removed to access the evaporator coil for cleaning. If it is not placed back flush against the housing, a gap forms where condensate drips past the tray instead of flowing to the drain outlet.
• A leak that starts immediately after servicing — on a unit that was dry before — almost always points to something that was moved during the service. The drain tray is the most commonly displaced component.
• Reseating the tray and running a water test confirms the fix. No parts, no damage investigation, and no coil inspection are needed if the tray alignment resolves the drip.
• If a post-service drip worsens as the day goes on, it follows the condensate production curve. More humidity means more water on the coil, and a misaligned tray spills faster as the volume increases.