An air conditioner removes moisture from the air as it cools. In Dubai’s humid months that can be several litres a day from a single unit. That water collects in a tray under the coil and runs away through a drain pipe. When water appears on your wall or floor, something in that path has gone wrong.
The five most common causes
1. A blocked drain line
By far the most common cause. Dust, algae and slime build up inside the drain pipe until the water backs up and overflows the tray. It usually starts as an occasional drip and gets worse over a few weeks.
2. A dirty filter or coil that freezes
When airflow is restricted, the coil gets too cold and ice forms on it. When the unit cycles off, the ice melts faster than the tray can drain and water spills out. If you see frost on the pipes or the coil, switch the unit to fan only and call for a service.
3. Low refrigerant
A system that is short of gas can also cause the coil to freeze, with the same result. Low refrigerant means there is a leak somewhere, which should be found and repaired rather than simply topped up.
4. The unit is not level
If the indoor unit was mounted with a slight tilt, or the bracket has moved, water runs to the wrong end of the tray. This is common after renovations or when a unit has been reinstalled.
5. A damaged tray or disconnected pipe
Older units can develop cracks in the drain tray, and drain pipes inside false ceilings sometimes come loose. In ducted systems the leak can show up some distance from the unit itself.
What you can safely check yourself
- Switch the unit off at the remote and at its isolator before touching anything
- Wash the filters and let them dry before refitting
- Look for ice on the coil or copper pipes. If you see it, run the fan only for an hour
- Check that the drain outlet outside or on the balcony is not blocked or crushed
- Put a towel under the unit to protect the floor and furniture until it is fixed
Do not pour chemicals into the drain or try to remove the unit cover if you are not sure how. Water and electricity sit very close together inside an AC.
Why it is worth fixing quickly
A dripping AC rarely fixes itself. Water soaks into gypsum ceilings, which sag and stain, swells joinery and feeds mould behind walls. In apartment buildings it can reach the unit below, which turns a small repair into a dispute with neighbours or building management.
How we fix it
We find out where the water is coming from first. Most of the time the drain line needs flushing and the tray and coil cleaning, which is done in one visit. If the coil is freezing, we check the airflow and refrigerant pressure. If the unit is out of level, we reset it on the bracket.
Prices and booking are on our AC service and repair page. If a ceiling has already been damaged, our gypsum team can repair and repaint it on the same job.
