An air conditioning unit leaking water is one of the most common and sometimes the most disruptive building service problems – due to unit locations – in a workplace environment.

Leaking air conditioning units generally occur over the summer months where their use and the need for cooling increases. This is not exclusively a summer issue, but it is wise to be more vigilant during warm weather.

Leaking air conditioning units can ruin ICT equipment – as units are often installed side-by-side with important computing equipment – especially in areas where space is limited. Leaks can also cause discolouration and staining on walls and ceilings.

This video shows how an air conditioning unit caused a leak above the ceiling, resulting in water damage to ceiling tiles. The drip tray cracked and broke, spilling water from the condense system to the false ceiling below. The damage could have been a lot worse, were it not for a proactive facilities manager, who noticed the ceiling tile.

6 common causes of air conditioning units leaking

1. Dirty or blocked air filters

Air filters can become dirty or excessively blocked over time. The resulting restricted air flow can then cause excessive moisture condensing within the unit. This is because less air can pass through blocked filters, resulting in a system imbalance between optimal air flow and cooling. The restricted air flow will be met by an excess of cooling, with the moisture from the air freezing on the cooling coil. When the unit is switched off and the cooling coil defrosts, water fills the drip tray. If there is an excessive volume of water, the drip tray could become overcome and leak.

2. Broken condense pump

When a drip tray fills with water, it is important that this water is brought away from the unit as soon as possible. This is the job of the condense pump, located within the air conditioning unit. The condense pump drives the drip tray water to the condense drain and out of the air conditioning unit. If the pump malfunctions, it will not be able to pump away the water and thus cause the air conditioning unit to leak.

3. Blocked or broken float switch

A float switch in an air conditioning unit basically operates as a water sensor. If a float switch becomes blocked or broken, the water accumulated in the drip tray has nowhere to go. This issue typically occurs when shifting from periods when an air conditioning unit is not in use, into the summer cooling period.
The condense system can dry up and cause the drain float to become stuck. When the air conditioning unit is then switched on, the float in the condense system might not rise to activate the pump or allow water to flow to the drain, thus water leaks.

4. Blocked condense pipe

The condense pipe plays a vitally important role in an air conditioning system. Its job is effectively to discharge the water from the unit to an outside drain, keeping walls, ceilings and important ICT equipment safe from potential water damage.
A condense pipe can gather dust and dirt particles. Overtime an accumulation of dust and dirt can block the condense pipe. In effect, the water to be removed from the air conditioning unit has nowhere to go, backs up into the drip tray and then leaks from the unit.
This video below displays the inside of an air conditioning unit and a blocked drip tray and condense pipe.
view video

5. Broken or separated condense hose/pipe

Damage to the condense pipe is a frequent problem with air conditioning unit installations. Damage can be caused from accessing other systems in close proximity or simply be that poor installations weren’t discovered, due to their out of sight locations, above ceilings. This is exampled in the two videos below.
The first video shows how an unsecured condense hose/pipe separated in an out of sight location and caused a leak, above the ceiling. A simple extra fixing in this case solved the problem and secured the condense pipe.

This video displays a broken rubber seal and cracked pipe on a large air conditioning unit. Again, this was in an out of sight location, above the ceiling and it involved a break in the condense system.

6. Inefficient fan

An inefficient fan can cause the same effect as dirty or blocked filters. This is because an inefficient fan won’t deliver the same air flow as an efficient fan, resulting in reduced air flow into the air conditioning unit.
As less air passes through, an imbalance results between air flow and cooling in the system. The reduced air flow will be met by an excess of cooling, with the moisture from the air freezing on the cooling coil. When the unit is switched off and the cooling coil defrosts, water fills the drip tray. If there is an excessive volume of water, the drip tray could become overcome and leak.

What can a facility manager do?

The good news is that the risk of each of these issues occurring are easily preventable, by applying the following measures.

1. Planned preventative maintenance (PPM)

PPM is a risk averse measure that services plant items, such as, heating, ventilation and air conditioning (HVAC) units at set intervals to decrease the risk of failure. PPM is a proven cost-effective solution, providing comfortable conditions that support your business needs. Unmaintained plant will eventually fail to function, become troublesome or perform at levels that are inefficient.
Servicing and maintaining air conditioning units includes, cleaning filters and drip trays, clearing condense pipes, inspecting units, testing and proving their efficient operation. While scheduling PPM in the lead up to the traditional summer cooling period of May is advised.

2. Visual inspections

Being proactive around air conditioning units in warm weather – when the systems are more in demand – may uncover issues before they cause major damage. Visual inspections of units and the area around them for discolouration of ceiling tiles or signs of water – shown in the above video – can save time and costly repairs.

3. Switch off leaking air conditioning units

In the event of any water leaking, switch off air conditioning units and callout a service engineer to examine and fix the issue. Also ensure that a competent service engineer examines your system by checking F-Gas Registration’s database of certified companies.

Thermodial’s air conditioning approach

At Thermodial our mission is to improve air conditioning reliability by reducing callouts and saving on energy consumption. Not only will you save money on reduced callouts, but a saving can also be obtained from repairs to building fabric and equipment. As a result, your business will operate more efficiently, benefiting staff, customers and the environment.

Explore our full air conditioning PPM capabilities.