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Water Coming Out of AC Trunking: Causes & Solutions

Author : Letscool Aircon | Published On : 26 Oct 2026

Aircon Trunking

An air conditioner is essential for maintaining a comfortable indoor environment, especially during hot and humid weather. However, noticing water coming out of aircon trunking can be frustrating and may indicate an underlying problem with your air conditioning system. If left unresolved, this issue can lead to water stains, wall damage, mould growth, and reduced cooling performance.

Understanding why water leaks from aircon trunking and how to fix the problem can help you prevent costly repairs. In this article, LetsCool Aircon explains the common causes of aircon trunking water leaks, practical solutions, and preventive maintenance tips to keep your air conditioning system running efficiently.

What Is Aircon Trunking?

Aircon trunking is a protective casing used to cover and organise air conditioning pipes, refrigerant lines, drainage pipes, and electrical cables. It provides a neat appearance while protecting essential components from dust, accidental damage, and external exposure.

When water starts dripping from the trunking or collecting around its joints, it usually means moisture is escaping from the drainage system or forming on cold surfaces. Identifying the source of the leak is important before attempting any repairs.

1. Blocked Aircon Drainage Pipe

One of the most common causes of water coming out of aircon trunking is a blocked condensate drainage pipe. During normal operation, an air conditioner removes moisture from the indoor air. This moisture collects in the drainage tray and flows outside through a drainpipe.

Over time, dust, dirt, algae, and other debris can accumulate inside the pipe. When the blockage prevents water from draining properly, moisture may overflow from the drainage tray and escape through the trunking. Ductless Aircon

Solution: Have the drainage pipe inspected and cleaned to remove the blockage. A professional aircon technician can flush the drainpipe, check the drainage tray, and ensure that water flows freely. Regular cleaning helps prevent recurring leaks and maintains efficient air conditioner operation.

2. Incorrectly Installed Drainage Pipe

Proper drainage pipe installation is essential for preventing aircon water leaks. The pipe generally requires a suitable downward slope so that condensation can flow away naturally.

If the drainage pipe is installed with an insufficient slope, has an upward section, or contains poorly connected joints, water may accumulate instead of draining properly. Eventually, the trapped water can leak into the aircon trunking.Aircon Maintenance 

Solution: Ask a qualified aircon technician to inspect the drainage pipe alignment, connections, and slope. Correcting installation problems can restore proper drainage and reduce the risk of future water leakage.

3. Damaged or Loose Drainage Connections

Aircon drainage pipes and their connections can deteriorate over time. Loose joints, cracked pipes, and damaged connectors may allow condensation to escape before reaching the designated drainage outlet.

You may notice water dripping from trunking joints or damp patches appearing along the wall beneath the air conditioning unit. 

Solution: Inspect accessible drainage connections for visible damage or looseness. Damaged sections should be repaired or replaced using suitable components. If the leak originates inside the trunking, professional inspection is recommended to avoid damaging concealed pipes or electrical wiring.

View more: how to connect your aircon to a mobile app

4. Poor Insulation Around Refrigerant Pipes

Air conditioning systems contain refrigerant pipes that become cold during operation. These pipes require appropriate insulation to prevent moisture in the surrounding air from condensing on their surfaces.

When insulation is damaged, missing, or improperly fitted, condensation can form around the pipes. Water may then collect inside the trunking and escape through openings or joints.

This problem is particularly common in humid environments, where warm air contains significant amounts of moisture. Aircon Steam Cleaning 

Solution: Have the refrigerant pipe insulation inspected and replaced wherever necessary. Ensure that insulation covers the required pipe sections and that joints are properly secured. Correct insulation helps minimise condensation and improves overall system efficiency.

5. Dirty Aircon Filters and Evaporator Coils

Dirty air filters restrict airflow through the indoor air conditioning unit. Reduced airflow can cause the evaporator coil to become excessively cold and, under certain conditions, develop ice.

When the ice melts, the resulting water may exceed the drainage system's capacity or spill from the drainage tray. If the drainage system is already partially blocked, water may escape through the trunking.

Dirty evaporator coils can also interfere with normal airflow and cooling performance.

Solution: Clean or replace the air filters according to the manufacturer's recommendations. If the evaporator coil is dirty or ice has formed, arrange for a technician to inspect the system. Avoid repeatedly restarting an air conditioner that is freezing up, as the underlying cause needs to be identified.

6. Damaged or Overflowing Drainage Tray

The drainage tray collects condensation produced by the evaporator coil. If the tray is cracked, incorrectly positioned, corroded, or overflowing, water may escape into the surrounding casing and aircon trunking.

A damaged tray can cause persistent leakage even when the drainage pipe is relatively clear.

Solution: A technician should inspect the drainage tray for cracks, blockages, and alignment problems. Depending on the condition, the tray may need cleaning, repositioning, or replacement to restore proper water collection.

7. High Humidity and Excessive Condensation

High humidity can increase the amount of moisture removed from indoor air. When warm, humid air comes into contact with inadequately insulated cold pipes or surfaces, condensation may form around the air conditioning installation.

This moisture can collect inside the trunking, particularly if ventilation is limited or insulation is damaged. Aircon service price

Solution: Check the insulation around cold pipes and ensure that the drainage system is functioning correctly. Regular aircon servicing can help identify condensation-related problems before they cause significant water damage.

How to Prevent Water Coming Out of Aircon Trunking

Preventive maintenance is one of the most effective ways to reduce the risk of aircon trunking leaks. Consider these practical steps:

  • Schedule regular servicing: Professional maintenance helps identify blocked drains, damaged insulation, and other potential problems.

  • Clean air filters regularly: Clean filters support proper airflow and reduce the risk of evaporator coil freezing.

  • Inspect visible trunking joints: Look for damp patches, water stains, loose covers, or signs of moisture.

  • Maintain the drainage system: Ensure that condensate can flow freely through the drainpipe.

  • Check pipe insulation: Replace damaged or deteriorated insulation to minimise condensation.

  • Address leaks early: Do not ignore occasional dripping, as small leaks can develop into more serious problems.

The appropriate servicing frequency depends on usage, environmental conditions, and the manufacturer's recommendations.

When Should You Call an Aircon Professional?

Although cleaning accessible air filters is a manageable maintenance task, persistent water leakage requires a closer inspection. Contact a qualified technician if water continues to emerge from the trunking, the indoor unit develops ice, cooling performance decreases, or damp patches repeatedly appear on walls and ceilings.

If water is near electrical outlets, switches, or wiring, avoid touching wet electrical components. Switch off the air conditioner if it is safe to do so, and seek professional assistance. If there is an immediate electrical hazard, keep clear and arrange appropriate emergency assistance.

A professional technician can identify whether the issue involves drainage, insulation, the evaporator coil, or another internal component. Accurate diagnosis helps prevent unnecessary repairs and recurring leaks.

Conclusion

Water coming out of aircon trunking is a problem that should not be ignored. Common causes include blocked drainage pipes, incorrect pipe installation, damaged connections, poor insulation, dirty filters, and overflowing drainage trays. Identifying the source early can help prevent property damage and maintain reliable cooling performance.

Regular cleaning, proper insulation, and timely aircon servicing can significantly reduce the risk of water leakage. If your air conditioner continues to leak despite basic maintenance, professional inspection is the safest way to identify and resolve the underlying problem.

LetsCool Aircon can be mentioned as your brand when publishing helpful air conditioning maintenance content for homeowners and businesses. By understanding the causes of aircon trunking leaks and taking preventive action, property owners can enjoy a cleaner, more comfortable indoor environment while helping their air conditioning systems operate efficiently.

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