01
Possible causes
Several issues can produce the same symptom. A technician may need to inspect the unit before confirming the cause.
- Clogged Drain Line — The drain pan collects condensation and drains it outside through a pipe. In humid Philippine conditions, algae and mold grow in the drain line, clogging it. Water then overflows into your room.
- Dirty Evaporator Coils — Dust and mold on the evaporator coils cause uneven condensation. Water droplets form in irregular patterns and miss the drain pan entirely, dripping directly from the unit.
- Frozen Evaporator Coil — When the coil freezes due to low refrigerant or poor airflow, the ice eventually melts and overwhelms the drain pan. You will notice intermittent leaking followed by a large water dump.
- Improper Installation — The indoor unit must be installed with a slight tilt toward the drain side. If installed level or tilted incorrectly — a common issue with budget installation services in the Philippines — water pools and overflows the wrong side.
02
Checks you can do safely
Turn the unit off before opening panels or cleaning accessible filters. Stop if the unit shows electrical damage or exposed wiring.
- Locate and clear the drain line — Find the white PVC drain pipe exiting your wall. Use a wet/dry vacuum to suction out the clog from the outdoor end. Alternatively, pour a cup of diluted bleach (1:10 ratio) into the drain pan to kill algae.
- Clean the air filter immediately — A dirty filter causes the coil to freeze and then flood. Clean the filter as your first step — this resolves the leak in many cases without any further action.
- Check the drain pan for cracks — Remove the front cover and inspect the plastic drain pan below the coil. Cracks or warping from age allow water to bypass the pan. Small cracks can be sealed with waterproof epoxy.
- Verify the unit tilt — Place a spirit level on top of the indoor unit. It should tilt 2–3 degrees toward the drain end. A level or reverse-tilted unit will always leak regardless of other factors.
03
When to request a technician
Book a diagnostic visit when the issue persists or any of these conditions apply.
- The drain pan is cracked or severely corroded
- Water leaks from the wall or ceiling around the unit (may indicate pipe routing issues)
- The unit was recently installed and already leaking — warranty issue
- You cannot locate or access the drain line
- Leaking resumes within 1–2 days of clearing the drain (severe algae blockage requiring chemical treatment)
04
Reference cost
Basic cleaning including drain flush: ₱500–₱800. Drain pan replacement: ₱800–₱2,000. Full installation correction: ₱1,500–₱4,000.