Reasons for water leakage in fan coil units and common troubleshooting

January 30, 2024

Reasons for water leakage in fan coil units and common troubleshooting


Fan coil unit with fresh air system is currently a widely used air conditioning method, which is widely used in hotels, offices, hospitals, and other buildings due to its flexible layout and independent adjustment of each room. However, errors in construction and design often lead to many problems, among which the most common is water leakage.


Fan coil system generally has irregular fittings such as valves, filters, and hoses connected to the coil at the engineering site. The insulation is not easy to compact, and it is often disassembled during daily maintenance, which can easily cause condensation water leakage. In engineering practice, the method of slope the local supply and return water pipeline towards the side of the coil can be used to prevent and remedy.


The poor drainage of condensate water is often manifested as the overflow of condensate water from the connection plate of the fan coil unit. During the operation and use of the air conditioning system, local excessive force or failure of the support and hanger can easily cause changes in slope or local water accumulation, which can easily cause condensate water overflow. This requires strict control of the slope of the water pipe during installation, unblocking the drainage pipeline, and controlling the reasonable spacing with other pipelines. Do not get too close to prevent accidental deformation due to force. And check the installation and fixing points of the supports and hangers to prevent deformation and detachment.

During the construction process, some people believe that as long as water enters from the highest point of the condensate pipe network and can flow out from the lowest point, it is not enough to only flow out. It is also necessary to ensure that the same amount of water enters and exits. Otherwise, there will be local water storage problems, and problems such as fan coil air conditioning can easily accumulate impurities and breed bacteria and moss, which can easily block pipelines over time. This kind of problem must be strengthened in construction management, and it is difficult to detect and deal with after the insulation of the condensate pipe.

Every device has certain shortcomings, and we will not negate the existence and use value of the device just because it has shortcomings. As long as we use it reasonably, they can be used well for us. The same applies to common fans in our production and life. The use of axial fans requires users to distinguish advantages and disadvantages well, and make good use of them to better play a role, How can we achieve the reasonable and proper use of fan coil units?

Reasonable use is limited and cannot be separated from proper maintenance and upkeep. Therefore, it is necessary to establish a comprehensive maintenance management system. Regular maintenance work is an important link to improve the reliability of axial flow fans. Based on the user's experience, it can be concluded that adopting different means and methods for different faults can greatly reduce the number and frequency of unplanned shutdowns of fans. Therefore, these all require the technology of axial fans to be more complete and reliable.


Usually, when facing the use of fans, we also need to learn how to deal with some of the fan's fault problems, such as surging, stalling, and snatching wind. These are all part of the fan's fault problems, and solving these problems requires users to have very professional skills and make quick judgments based on the fault. In response to the fault that occurs, maintenance personnel must understand the equipment's operating conditions, Be able to analyze and determine the cause and frequency of faults, and quickly deal with the causes of oil pressure fluctuations affecting the operation of the fan. Also, be familiar with the impact of the opening of the moving and stationary blades on the operation of the fan.

In addition, the nut used to fix the feedback bearing may loosen due to vibration and other reasons of the fan, which can also cause the feedback rod to malfunction. The feedback rod cannot drive the outer sleeve of the wrong oil valve to move, nor can it seal the oil inlet of the regulating system. The fan blades can only slide towards the fully open or fully closed direction, and ultimately stabilize at the limit position by mechanical limit.

Although axial fans have some unavoidable drawbacks, as long as we avoid these uncertainties well during use, the effectiveness of the fan can be well guaranteed, and the frequency of faults occurring during use will also be greatly reduced.

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Reasons and solutions for water leakage in fan coil units:

1. If water leaks outside the collection tray of the fan coil unit, it is mainly due to a problem with the insulation material, which needs to be strengthened to eliminate it.

2. If water leaks into the collection tray, it means that the condensate pipe of the fan coil unit is blocked and the condensate water overflows. We just need to unblock the condensate pipe. Prepare a plastic pipe that is 4-5 meters long, with one end inserted into the condensate discharge pipe and the other end connected to the bathroom faucet (which can be made into a small joint and threaded onto the faucet), and use the pressure of water to unblock the pipe or blow it with a carbon dioxide cylinder.

It should be noted that the phenomenon of blockage in the condensate pipe of the fan coil unit is common. This is mainly due to the presence of water in the fan coil unit, coupled with the appropriate temperature, which can easily promote the growth of algae and produce a sticky, smooth and extremely thick residue, blocking the condensate pipe. It is recommended to place algae killing drugs in the collection tray of the fan coil unit to reduce its harm.

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3. If the condensate discharge pipe of the central air conditioning fan coil unit is always blocked, water often leaks from above. Once blocked, there will be a lot of biological sludge and it will be dirty. In addition to regular cleaning, it is recommended to thoroughly flush and descale the system, check whether the return air outlet of the fan coil unit is equipped with a filter screen, and whether the pipeline installation slope meets the requirements.

Of course, cleaning is a method that addresses the symptoms rather than the root cause. The reason why the condensate water in the fan coil unit is often blocked is because there is too much dust in the area where the equipment is located, and the drip tray is often contaminated. In fact, the so-called biological scale is basically environmental pollution. Besides cleaning, maintenance of the equipment is the most important.


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