Precautions for Routine Maintenance of Cooling Towers

2025-04-27

Regarding Maintenance:

The V-belt of the blower may stretch slightly during the initial operation. Please adjust the tightness of the belt appropriately according to the adjustment instructions. If it is tightened too much, it will damage the bearing and cause an accident.
Please clean the water dispersion holes of the upper water tank and the filter screen of the lower water tank regularly once a month.
When the unit is out of operation, please loosen the belt, lubricate the bearing part of the blower, and cover the motor. Determine the tightness of the belt during the initial operation, tighten the nuts, lubricate the bearing part of the blower, and also check whether there are bird nests or foreign objects in the tower before starting the operation.
Replace the circulating water at least twice a year.
After the circulating water evaporates, the dissolved substances in the water will be left behind, increasing the water concentration. After the water is concentrated, the corrosiveness increases, scale is formed, reducing the cooling tower's capacity and damaging the pipes and equipment. To prevent this situation, it is recommended to solve it by draining part of the circulating water:
① Open the drain valve only a little during operation (please close the drain valve when the operation stops);
② Clean the lower water tank and change the water regularly;
③ Raise the operating water level to make water overflow frequently;
④ Install an automatic water changing device.

Precautions during Winter Shutdown:

Drain the circulating water and the sprayed water.
In the case of a closed type, please open the drainage and exhaust ports of the circulating water and the drain valve of the water spraying pump.

Precautions during Winter Operation:
Please note that the current of the motor will increase during winter operation.
To prevent the lower water tank from freezing, please use an anti-freeze electric heater.
Use heaters for the water spraying pump and pipes, and insulate the water level of the lower water tank.
To prevent the copper pipes (radiators) of the closed cooling tower and the sprayed water from freezing, please pay attention to the following points:
① To prevent the circulating water from freezing, please add antifreeze to the circulating water or install auxiliary anti-freeze electric heaters in the pipes.
② After adding antifreeze, the freezing temperature drops, making it less likely to freeze. The higher the concentration of the antifreeze, the lower the freezing temperature, but the thermal conductivity will decrease. Therefore, pay attention when selecting the cooling tower. In addition, if there is a water leak, the added make-up water will dilute the antifreeze, raising the freezing temperature. Please note this.
③ When the circulating water pump is running, the anti-freeze electric heater heats the water, and it will not freeze. If the circulating water pump stops, an auxiliary circulating water pump is required. Here, we recommend using a complete set of anti-freeze equipment (including the auxiliary circulating water pump, anti-freeze electric heater, and pipes).
④ Install a three-way valve in the circulating water system. When the circulating water controls the capacity through the bypass pipe, increasing the flow rate of the bypass pipe will reduce the flow velocity in the copper pipe, and freezing may occur even under load. Please set the minimum circulating water volume of the cooling tower.
⑤ To prevent the water spraying pump and the water spraying pipes from freezing, please use an anti-freeze electric heater to maintain the temperature of the lower water tank.

Others:

Before operation, operation, and work, you must read the operation and maintenance instructions, and please abide by the prohibited items and work instructions.
Never enter the cooling tower during operation. And do not climb to the upper part of the tower body.
When the blower may be running, never touch the blower.
The anti-freeze electric heater will generate heat. Please do not touch it with your hands.
Please do not drink the water in the cooling tower. If it gets into your eyes, rinse immediately. After the work, rinse your mouth and wash your hands.
There are warning labels and attention labels pasted on each part of the tower body. Please abide by the contents recorded on the labels.

Precautions for Cooling Tower Design and Selection:
Regarding the Installation Site:

The cooling tower should be installed in a ventilated place.
Try to avoid places with a lot of dust, acidic exhaust, high-temperature exhaust, and a large amount of water vapor. Especially after inhaling a large amount of soot, not only the cooling tower but also the pipes and other equipment will be corroded.
If there are obstacles or a small interval between the louver surface and the wall, air intake will encounter impedance, resulting in a decrease in cooling capacity. Please maintain the following distances:
Cooling Capacity L Dimension:
5 ～ 15RT: More than 0.5m;
20 ～ 70RT: More than 1.0m;
80 ～ 100RT: More than 2.0m;
110 ～ 175RT: More than 2.5m;
200 ～ 400RT: More than 3.0m;
Above 500RT: More than 3.5m.
Note: If the obstacle is an outer wall and the outer wall can be opened, the L dimension can be adjusted appropriately according to the opening area and the opening rate. In addition, the L dimension can also be adjusted appropriately according to the height of the outer wall. Please consult the cooling tower manufacturer.
When the obstacle is higher than the cooling tower, in order to prevent air short-circuiting, please add a straight pipe.
Pipe according to the pipe dimensions recorded in the sample.
The pipes and the water pump should be installed below the operating water level of the cooling tower to prevent air from being sucked in.

Regarding the Heat Resistance Temperature:
The filler is made of rigid polyvinyl chloride resin (PVC). The inflow of high-temperature water will cause deformation. In the case of the standard type, the maximum operating temperature is 45°C. Pay special attention to the excessive flow rate and high-temperature water during the trial operation. In addition, for temperatures above 45°C, some powerful manufacturers have heat-resistant fillers available. Please consult the cooling tower manufacturer.

Regarding Noise Countermeasures:
The sound values vary depending on the installation conditions of the cooling tower. If there are noise requirements, please consult the cooling tower manufacturer in advance.

Regarding the Makeup Water Volume:

Evaporation Rate (WE) kg/h
The circulating water in the cooling tower is continuously evaporating during operation. The evaporation rate is calculated by the following formula:
WEQ/R = (Tw1 - Tw2) × L × Cp/R
In the case of general air conditioning with WB = 27°C, (Tw1 - Tw2) = 5°C, Q: Cooling Heat (KJ/h) = (Tw1 - Tw2) × L × Cp. R: Latent Heat of Evaporation of Water (2520KJ/kg), L: Circulating Water Volume (kg/h), Cp: Specific Heat at Constant Pressure (4.2KJ/kg°C). It can be obtained that: WE = 0.0083 × L, that is, 0.83% of the circulating water volume is evaporated.
Drift Rate (WD) kg/h
It varies depending on the structure of the cooling tower and the ventilation speed. Generally, the maximum drift rate does not exceed the following values:
For the open type, 0.3% of the circulating water volume; for the closed type, 0.15% of the circulating water volume.
Makeup Water Volume ΔW (l/min)
The makeup water volume is the sum of the above two items. The specific gravity of water is 1 (kg/l).
For the open type used in air conditioning: 1.13% of the circulating water volume; for the closed type: 0.98% of the circulating water volume.
For safety reasons, generally, 1.5-1.7% of the circulating water volume is required.
Blowdown Water Volume WB (kg/h)
The blowdown water volume varies depending on the water quality and the concentration multiple. In the case of general air conditioning, for both the open type and the closed type, add 0.3% of the circulating water volume to the above water volume.
Selection of the Water Supply Pipe
The selection of the water supply pipe is calculated according to the makeup water volume, the water supply pressure, and the flow characteristics of the float valve. Especially in the case of a natural drop water tank with low makeup water pressure, please consult the cooling tower manufacturer in advance.

Key Points to Note during Cooling Tower Operation:

Please connect the wires of the motor according to the operation direction arrow marked on the blower.
Please confirm again whether the switch, fuse, and wiring are configured according to the capacity of the motor. Single-phase operation will burn out the motor. It is recommended to use an overcurrent protector.
Before the initial operation of the circulating water pump, when the pump is stopped, fill the pipes with water. Open the valve, start the pump, and slowly open the valve. If you start the pump with the valve open, the impact of the water will damage the components inside the cooling tower. Pay attention to the operation of the water level in the lower water tank until all the pipes are full of water. Use the makeup water pipe to fill the water until the operation water level of the lower water tank stabilizes before continuous operation. At this time, please note that the filter screen should not suck in air. Use a water flow meter, etc. to measure the operation water level, and adjust the water flow rate by adjusting the angle of the valve.
If there is a load, start the pump and then add the load after the circulation starts. If you add the load when the water volume is unstable, it will cause the inlet water temperature to be abnormally high.
An unbalanced water level in the upper water tank will lead to insufficient cooling capacity. Please adjust the water level of each water tank with the water distribution valve or the valve of the pipe.
Please adjust the float valve to the operation water level.
If there is an anti-freeze electric heater installed, please note that it should not be burned empty to cause a fire.
Welding slag and iron powder from pipe cutting left during pipe construction are very harmful to the copper pipes of the chiller and are also the reasons for the deterioration of the water quality. Please clean the pipes during the trial operation period.
In the case of using a closed cooling tower, the circulating water pipes are closed pipes. To withstand the expansion of the water in the pipes, please install an expansion tank. The normal pressure of the tank is below 0.49MPa.
For the pump of the closed cooling tower, turn it by hand before powering it on.

Precautions during Cooling Tower Installation:
Key Points to Note Regarding Pipes and the Water Pump:

When connecting the pipes, please do not deform the cooling tower body or the interface due to correcting the inclination of the pipes. Especially when screwing in the pipes, please fix the interface at the same time.
Please do not install the pipes above the operation water level of the cooling tower. Otherwise, air will be sucked in when the operation starts, and water will overflow when the operation stops.
Try to use flexible joints for the joints connected to the cooling tower. In this way, the pipes will only vibrate by themselves and will not affect the cooling tower.
Please install valves on each pipe. In this way, it is easy to clean the cooling tower, and it can also be used as a freezing prevention measure when the operation stops. For the convenience of operation, please do not install valves under the cooling tower.
Please connect the drainage and the overflow water to the drainage pipe. A valve must be installed for the drainage, and it should be designed for natural drop drainage. Do not install a valve on the overflow pipe.
When piping, please never process the components of the cooling tower. Otherwise, it will affect the structural strength of the cooling tower.

Precautions for the Foundation:

Each foundation part of the cooling tower should be on the same horizontal line. If there is a slight difference in the foundation level, please adjust it with shims.
In the case of a connected type and multiple chambers, please confirm whether there are no gaps between each chamber.
After installing the cooling tower on the foundation, please fix and tighten the foundation bolts. During the trial operation, please confirm again whether the foundation bolts are tightened. If there is a steel frame on the foundation, please tighten the bolts of the steel frame.
When there is an anti-vibration device installed, confirm whether the foundation or the steel frame, the anti-vibration device, and the cooling tower are tightened, and confirm according to the installation instructions of the anti-vibration device.