Why does my condo aircon leak again after a wash?
A condo aircon that leaks again soon after a wash usually has a clog further down the line, in the drain pipe concealed in the wall or false ceiling. The wash cleans the indoor unit, but water still cannot reach the floor trap. Clearing the whole concealed pipe, end to end, stops the leak. Key takeaways
- The clog hides in the wall: many condo drain pipes run concealed to a floor trap, out of reach of a normal wash.
- A clean unit can still leak: water backs up from the blocked pipe into the drain pan and spills out.
- The floor trap tells you: little or no water reaching it while the aircon drips points to the concealed pipe.
- High pressure clears it: we push the dirt through the pipe until the water at the floor trap runs fast again. In the video above, the owner had used us before, then tried another company for their latest wash. Not long after, the aircon was leaking again. We lifted the floor trap cover, blew high-pressure air through the concealed pipe, and the dirt came out at the trap. The last shot shows the water running fast again. With the leak fixed, the owner asked about our quarterly servicing package for all 4 of their units.
How to tell if the concealed drain pipe is the problem
- Find the floor trap the aircon drains to. In condos it is usually in a bathroom, the yard or the balcony.
- Run the aircon for 15 minutes on a cool setting.
- Check the indoor unit first. If no water drips or leaks from it, nothing is clogged, even when little water reaches the floor trap.
- Compare both ends. If water drips from the indoor unit while little or none reaches the floor trap, the concealed pipe is likely clogged.
- If the unit leaks but water reaches the trap normally, the leak is in the unit itself: a dirty coil, a slimy drain pan or a frozen coil. See why an aircon leaks water for those causes. If step 4 matches, switch the aircon off and book our aircon water leaking repair. Dripping right now? Message Luna on WhatsApp.
Why do concealed drain pipes clog?
When the aircon cools, the evaporator coil pulls water out of the air. That condensate runs into the drain pan and down the drain pipe. It carries dust and microbes that grow into slime on the pipe walls, the same build-up we describe in why aircon drain pipes clog with slime. In a condo, that pipe often runs inside the wall or above a false ceiling, sometimes for several metres, before it ends at a floor trap. This clog is common in condos, especially when servicing is skipped, or when an earlier service did not clear the pipe thoroughly. Three things make it worse:
Condo factor | Why it matters |
|---|---|
Pipe hidden in the wall | Nobody sees the slime building up until the water backs up |
Long run to the floor trap | More pipe wall for slime to grow on, and more places for dirt to settle |
| Gentle slopes inside the wall | Slow-moving water drops its dirt, and the plug grows there | A normal wash cleans the coil, blower fan and drain pan, and flushes the drain. If the pipe is already half blocked deep inside the wall, the flush slows down there, and a few days later the unit drips again.
How do we clear a clogged concealed drain?
We clear the whole path, from the aircon to the floor trap:
- Open the floor trap so we can see what comes out at the far end.
- Blow the concealed pipe clear. A high-pressure air blower forces the slime and dirt through the pipe and out at the floor trap. No wall is hacked. This is part of our servicing: we judge how bad the clog is and focus on clearing it properly, not on selling you extras.
- Flow test with water. Water should now run out at the floor trap fast and steadily, as it does at the end of the video.
- Clean the source. A slimy drain pan or dirty coil keeps feeding the pipe, so we clean the unit too. Our premium servicing PowerJet-washes the blower fan and drain pan and flushes the drain at every visit. If the pipe turns out to be broken or wrongly sloped inside the wall, we explain what we found and quote before any further work.
What it costs
Job | Price | What drives it |
|---|---|---|
Water leak fixed with premium servicing | S$80 for 1 unit | Drain pan, blower fan and coil cleaned, drain pipe cleared and flushed |
| Hard-to-clear concealed drain pipe | Part of the servicing | Cleared with the high-pressure air blower; we judge how bad the clog is and tell you before any other work |
When to call a technician
Call us if the aircon drips while the floor trap stays dry, if the leak comes back within days of a wash, or if water is running down the wall or staining the ceiling. If water has already reached the floor, read what to do in the first hour of an aircon leak. You can book online in under a minute, or ask Luna on WhatsApp at any hour.
Frequently asked questions
Why is my condo aircon leaking when it was just washed?
A wash cleans the coil, blower fan and drain pan inside the indoor unit. If the clog sits further down, in the drain pipe hidden in the wall, the water still has nowhere to go and backs up into the unit.
Can I pour water or a drain cleaner into the floor trap?
It will not reach the clog. The floor trap is the far end of the pipe, and the dirt sits somewhere between the aircon and the trap. Household drain cleaners can also damage the drain pan. The pipe has to be cleared from end to end.
Does clearing the concealed pipe mean hacking the wall?
Usually not. We clear it by blowing high-pressure air through the existing pipe, so the dirt comes out at the floor trap. If a pipe is broken or badly sloped inside the wall, we explain what we found and quote before any further work.
How do I stop the concealed drain from clogging again?
Regular servicing keeps the drain pan and pipe flushed before slime builds up. Aircons that run most nights in Singapore are best serviced every three months.
Is a leak after a recent service covered by your warranty?
If we serviced the unit and it leaks within 90 days, WhatsApp us photos or a video. The site inspection and fixing the leak are free under our servicing warranty.
Eric Lim, aka Uncle EricFounder of iAircon.Repair, now in its 10th year servicing aircons in Singapore. Some of our jobs are filmed, and you can watch the work on YouTube.
