Number of views: 432 Author: AILI Industrial Release time: 2026-12-17 Source: Ai Li Industrial
The slope of the water receiving pan of the air-conditioning box should be designed together with the actual installation posture, the position of the drain outlet and the pan structure. The goal is to allow the condensate to flow to the outlet and reduce retention. If you only mark the slope on the map without checking the height of the drain outlet, the depression of the plate or the level of the site, water accumulation may still occur.
Confirm that dripping water from the coil and possible water-containing parts can fall into the water receiving range, and then check whether there are reverse slopes or steps around the bottom of the pan, the seams, and the drain outlet. The tilt of the equipment may change the original low point, and if the external drainage pipe is raised or stressed, it may also affect the discharge. Multi-zone water receiving structures should confirm their exits and cleaning paths respectively.
The collection range should cover the coil dripping and the designed water-carrying area; the slope direction should be continuous, and the bottom of the pan should transition toward the outlet to reduce local concave spots and obstructions; the site conditions should check the unit level, nozzle support, and drainage pipe direction. If any of the three is not implemented, the slope marking will be just a number on paper. For the influence of coil head-on wind speed on water entrainment, please refer toWhat impact does the coil head-on wind speed have on heat exchange and water entrainment in the air conditioning box?。
The drain outlet should be located at the actual low point of the drain pan, rather than setting the slope first and then finding the outlet. If the drain outlet deviates from the low point, condensation will accumulate in the lower part of the pan. Even if the slope seems reasonable, the actual drainage will not be smooth. When there are multiple rows of coils or water connections in sections, each area should have a clear drainage direction and outlet, and water cannot be relied on to flow over long distances in the tray.
Avoid bulges, weld buildup, or sealant obstructions around drain openings. The direction of the interface should be convenient for access and maintenance, and the outlet should not be set in a position that is difficult to operate just because of the pursuit of neat appearance. For the structural relationship between the water tray and the drain outlet, please refer toWhat is the difference between the positive pressure section drainage and the negative pressure section drainage of the air conditioning box?。
Uneven equipment foundations, uneven compression of the shock absorbing pads, or deformation of the base will cause the actual low point of the drain pan to deviate from the designed position. After installation, the levelness of the unit should be checked to confirm that condensate can flow toward the drain outlet. If the basic conditions cannot be adjusted, this should be stated before manufacturing, and the manufacturer will evaluate whether the slope or structure of the water tray needs to be adapted.
The foundation height and drainage space should also be checked together, please refer toHow to determine the foundation height of a horizontal air conditioning box based on drainage conditions? . If the drainage pipe needs to be raised or run horizontally for a long distance, it will also affect the discharge and cannot be solved by simply increasing the slope.
When draining water from the drain pan in the negative pressure section, the pressure inside the box that is lower than the outside world may cause air to be sucked in from the drain port, preventing the discharge of condensed water. Water seals or other design-confirmed drainage structures are used to isolate this pressure difference and maintain discharge conditions, and should be sized based on the actual negative pressure and structure. For the difference in drainage between positive pressure section and negative pressure section, please refer toWhy does negative pressure drainage of air conditioning boxes often require water sealing?。
Insufficient water seal height or water loss after shutdown may lead to abnormal drainage. During commissioning, it should be confirmed that the water seal is effective, and it should also be checked before re-operation after long-term shutdown. When multiple sections of water pans share a drainage pipe, it is also necessary to prevent air leakage between sections with different pressures.
Carry out controlled drainage inspection according to the project plan, observe whether there is any residue, backflow or interface leakage, and check the actual drainage conditions under the operating pressure of the unit. Just because it can drain water at rest does not mean it will be normal after it is turned on. The inspection should avoid allowing water to come into contact with parts that are not suitable for receiving water, and the results should be included in the commissioning records.
Drainage time, residual position and interface status can be recorded during verification. If water accumulation is found, you should first confirm whether it is a slope problem, a clogged drain outlet, or a water seal failure, and then decide on a treatment method instead of directly enlarging the drainage pipe or raising the slope.
Aili Industrial can check the layout of the water pan and drain outlet during structural confirmation. The on-site installation drawing should also provide the foundation height and external drainage direction. Aili's industrial manufacturing end covers sheet metal, complete machine assembly and air filters. The slope direction of the water tray, the position of the drain outlet and the box structure can be confirmed in the same package; non-standard water trays can be adjusted according to the site foundation and drainage conditions.
Product form can be viewedAir handling unit andFan box page; clean air supply package can be combinedFFU fan filter unit andEFU equipment end fan filter unit verification; terminal particle filtration can be combinedHEPA/ULPA filter confirmation; when it comes to gaseous pollution control, you can communicate separatelyChemical filter solutions. The specific drainage effect, applicable conditions and delivery scope still need to be verified based on the corresponding configuration data and on-site working conditions. Actual results are subject to on-site drainage inspection and performance test results.
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The slope of the water tray is marked, why is there still water accumulation on site?
It may be that the drainage outlet is not at the actual low point, the foundation is uneven, or the external drainage pipe is raised. Slope marking cannot replace on-site levelness and drainage path inspection.
Does the water tray in the negative pressure section have to be sealed with water?
Drainage in the negative pressure section usually needs to consider the impact of pressure difference on drainage. Whether to use a water seal and its size should be determined based on the actual negative pressure and structure.
Can Aili Industrial help check the water pan and drain outlet?
The structural layout can be checked based on the coil position, foundation height and drainage direction. The specific plan needs to be confirmed based on site conditions.
Check items |
Confirm key points |
Check items |
Confirm key points |
|---|---|---|---|
Collection scope |
Covers coil dripping and water carrying areas |
Continuous slope aspect |
The bottom of the plate transitions towards the outlet to reduce concave spots |
Drainage location |
Set at the actual low point of the drain pan |
site conditions |
Unit level, nozzle support and pipe direction |
Negative pressure drainage |
Water sealing structure and water sealing effectiveness |
Drainage verification |
Observe discharge and residue under operating pressure |
