Why Is My Aircond Leaking Water? Common Causes and Fixes

The Most Common Aircond Complaint in Malaysia

If there is one problem I see more than any other at PJ Kool Aircond Service, it is water leaking from the indoor aircond unit. In Malaysia’s hot, humid climate, this issue affects nearly every household at some point. The good news is that most water leaks have straightforward causes and can be resolved quickly by a professional technician.

Let me walk you through the six most common reasons your aircond is leaking water and what you can do about each one.

Cause 1: Clogged Drainage Pipe

Likelihood: Very High (60% of all leak cases)

This is by far the most common cause of aircond water leaks in Petaling Jaya and across Malaysia. Your aircond produces condensation as it cools the air, and this water is supposed to drain away through a small pipe to the outside of your home.

Over time, dirt, algae, and mould accumulate inside this drainage pipe and eventually block it. When the water cannot drain, it backs up into the drainage tray and overflows into your room.

The Fix

A professional technician will clear the blockage using compressed air or a flexible cleaning wire, then flush the entire drainage system with chemical solution and clean water. This is a standard part of any chemical wash service.

Can You DIY?

You can try pouring a small amount of diluted vinegar into the drainage tray to dissolve minor blockages. However, if the blockage is deep in the pipe, you will need professional help.

Cause 2: Dirty or Blocked Evaporator Coil

Likelihood: High (20% of cases)

When the evaporator coil is covered in dirt and grime, it affects more than just cooling performance. A dirty coil can cause ice to form on its surface. When this ice melts, it produces more water than the drainage system can handle, leading to overflow and leaks.

The Fix

A chemical wash is the only effective way to clean a dirty evaporator coil. The technician will apply chemical solution to dissolve the grime, then rinse the coil thoroughly. This restores proper heat exchange and prevents ice formation.

Signs This Is Your Issue

• You notice ice or frost on the indoor unit when you remove the front panel
• The aircond alternates between cooling normally and blowing warm air
• The leak is intermittent, not constant

Cause 3: Cracked or Misaligned Drainage Tray

Likelihood: Moderate (10% of cases)

The drainage tray sits beneath the evaporator coil and collects all the condensation before channelling it to the drainage pipe. Over time, this tray can develop cracks from thermal expansion and contraction, or it can shift out of position due to vibration.

The Fix

Small cracks can sometimes be sealed with waterproof sealant. If the tray is severely damaged, it may need to be replaced. A misaligned tray simply needs to be repositioned and secured properly. This type of fault calls for professional aircond repair and troubleshooting.

Signs This Is Your Issue

• Water drips from the centre or sides of the unit, not just from one corner
• The leak persists even after a chemical wash
• You can see visible cracks when the front panel is removed

Cause 4: Low Refrigerant Levels

Likelihood: Moderate (5% of cases)

When refrigerant (commonly known as gas) levels drop below the optimal level, the evaporator coil temperature drops too low and ice forms on the coil. As the ice melts, the excess water overwhelms the drainage system.

The Fix

A technician will check the refrigerant pressure and top up the gas if needed. However, low refrigerant usually means there is a leak somewhere in the system that also needs to be found and repaired. Simply topping up the gas without fixing the leak is a temporary solution at best.

Signs This Is Your Issue

• The aircond blows cold air for a while, then warm air
• There is ice visible on the copper pipes near the indoor or outdoor unit
• The leak gets worse as the day goes on

Cause 5: Improper Installation

Likelihood: Low to Moderate (3% of cases, mostly in newer units)

If your aircond was not installed correctly, the drainage system may not have the proper slope to allow water to flow freely to the outside. This is more common than you might think, especially with budget installations.

The Fix

The drainage pipe needs to be reinstalled with the correct downward slope. In some cases, the entire indoor unit may need to be repositioned. This requires a skilled installer who understands the importance of proper drainage angles.

Signs This Is Your Issue

• The leak started shortly after installation or reinstallation
• The leak happens mainly when the aircond runs for extended periods
• The drainage pipe appears to have a flat or upward section

Cause 6: Blocked or Disconnected Insulation

Likelihood: Low (2% of cases)

The copper pipes connecting your indoor and outdoor units are wrapped in insulation foam. If this insulation degrades, gets damaged, or was not installed properly, condensation can form on the pipes and drip inside your home.

The Fix

The damaged insulation needs to be replaced. This is a relatively simple and inexpensive repair, but it does require a technician to access the piping.

When Should You Call a Professional?

While minor issues like a slightly dirty filter can be addressed by homeowners, most water leak problems require professional diagnosis and repair. Here is a simple guide:

Call a professional if:

• Water is dripping onto electrical appliances or wiring
• The leak persists after you have cleaned the filters
• You notice ice formation inside the unit
• The leak has been ongoing for more than a day
• You see water staining on your wall or ceiling

You can try first:

• Clean or replace the air filters
• Check if the drainage pipe outlet outside is blocked by debris
• Ensure the unit is level and not tilted

PJ Kool Aircond Service Can Help

If your aircond is leaking water, do not wait for the problem to worsen. Water damage to your walls, furniture, and electrical systems can be far more expensive to repair than the aircond issue itself.

Contact PJ Kool Aircond Service for prompt, professional repair across Petaling Jaya, Kelana Jaya, Damansara, and the wider Klang Valley. We typically respond within 2 hours and offer same-day repair for urgent leak issues.