If water is near power points or the unit's wiring
Turn the air conditioner off at its isolator switch or at the switchboard before you look closer. Don't open the indoor unit's cover or touch any wiring. Mitsubishi Electric's own instructions say the unit should never be repaired by the user, because an improperly handled unit can cause electric shock, fire or water leaks.
Outside or inside? Start there
If the water is coming from the outdoor unit, relax. Samsung says the pipes get cold and form dew, and Mitsubishi Electric says condensed water drips from the outdoor unit in heating, and the defrost cycle melts ice that drips down. That's the system working.
Water from the indoor unit, or a damp patch on the wall below it, is different. Mitsubishi Electric says to stop using the air conditioner and get it looked at when water leaks or drips from the indoor unit.
Checks you can safely do yourself
Switch it off
Use the remote, then the isolator switch near the outdoor unit if there's one. Put a towel or bucket under the drip.
Look at the filters
Mitsubishi Electric says dirty filters cause condensation inside the unit. If yours are grey and furry, clean them as the manual describes. Our filter cleaning guide shows how.
Follow the drain hose outside
Samsung's checklist: the drain hose should point downward, run straight without bends or kinks, and its end shouldn't sit in water. A hose that's slipped, been crushed by a pot plant or ended up in a puddle is a common cause.
Check the hole in the wall
Samsung says rainwater can get in through the wall hole where the pipes go through, and suggests sealing it with putty or silicone. If the drip only appears after rain, this is a strong suspect.
Think about the weather and the windows
Mitsubishi Electric says not to run the unit for more than 4 hours in very humid conditions (80% humidity or more) or with windows or an outside door open, because condensation can drip and damage furniture.
When it needs a technician
Samsung says if water still drips after the hose checks, stop using the unit and book a professional inspection, and that a severe leak almost always needs a technician. The usual fixes are clearing a blocked drain, re-setting the fall on the drain line, re-levelling the indoor unit or replacing a failed condensate pump on units that have one.
Ask for an air conditioning repair specialist rather than a general handyman. Clearing the drain properly often means taking covers off and working near the electrics, which is a job for a licensed technician.
What's yours, and what's theirs
You can
- Switching the unit off and catching the water.
- Cleaning the filters the way your manual describes.
- Straightening a bent drain hose or lifting its end out of a puddle.
- Noting when it drips: only in cooling, only after rain, or all the time. It helps the technician.
Leave to a licensed installer
- Opening the indoor unit and clearing the drain tray and line.
- Re-levelling the unit or re-setting the drain's fall.
- Replacing a condensate pump.
- Anything involving the wiring or the refrigerant.
Signs it's more than a blocked drain
- Ice forming on the pipes or the indoor unit.
- The unit is blowing warm air as well as dripping.
- Water appearing inside the wall or the ceiling below the unit.
- A musty smell that comes back soon after the filters are cleaned.
What we'd do
Where we'd start
Switch it off, clean the filters and check the drain hose outside. Those three are quick, and they fix a lot of leaks. If it's still dripping inside after that, stop running it and have a repair specialist clear the drain before the water gets into the plaster.
