Debugging method of central air conditioning system

Debugging method of central air conditioning system

Before the central air conditioner is put into use, the entire system must be debugged. The commissioning of the central air-conditioning system can be divided into: cold water system, cooling system, terminal equipment and air-conditioning host.

　　 Commissioning the central air-conditioning system can reduce the hidden dangers of the central air-conditioning system and avoid various failures of the central air-conditioning system after it is put into use.

　　According to the characteristics of the central air-conditioning system, the commissioning of the central air-conditioning system can be divided into five links: chilled water system, cooling system, terminal equipment, auxiliary equipment and air-conditioning host. The purpose and steps of each commissioning link are different.

　　1. Debugging of cold water system

　　1.1 Cleaning of cold water pipe

　　Because the pipeline is prone to residual welding slag and other foreign matter during installation and welding, it must be cleaned before use. Otherwise it will cause blockage of the pipeline and damage the equipment in severe cases. To clean the cold water pipeline, firstly, the fan coils on each floor and the inlet valve of the air-conditioning host should be closed, and the water supply and return connection valve should be opened at the same time. Then turn on the circulating pump and run for 3h-5h. Finally, let off the water in the system, and clean the filter of the fan coil and the air conditioner one by one.

　　1.2 Collect the data of the pressure drop of the cold water branch pipe and the total pressure drop of the system

Open the inlet and outlet valves of the fan coil and the air conditioner, turn on the circulating pump to circulate for a period of time according to the design pressure, measure the pressure drop of each branch pipe and the total pressure drop of the circulating pump, and then increase the water pressure of the system to the commissioning pressure ( 1.6KPa or 16kg cooling and heating systems are subject to design requirements), turn off the circulating pump, keep it for more than 24h, and measure the pressure drop of each branch and the total pressure drop of the circulating pump again. Through the collection of these data and comparison with the design data, we can find the mistakes in the design and installation of the system.

　　2. Debugging of cooling system

　　2.1 Cleaning of cooling pipe

　　 The cleaning of the cooling pipeline is basically the same as the cleaning of the cold water pipeline. If there is no filter on the pipeline, it is recommended to install a filter at the water inlet and outlet of the air conditioner and the cooling tower. This is because the cooling tower is open, and the water quality is very easy to pollute, and it is easy to form precipitation inside the condenser.

　　2.2 Commissioning of cooling tower

　　The cooling tower is the key equipment of the cooling system. When debugging the cooling tower, it is necessary to make sure that the power supply is unblocked. Due to the large number of fans on the cooling tower, it is easy to mistake the power line during installation. After confirming that the power supply is unblocked, turn on the fan and observe the speed and direction of the fan at close range.

If you find that the fan does not turn, check whether the wiring is correct; if you find that the speed of the fan is very slow, check whether the line is lacking phase; if you find the fan is rotating in the wrong direction, you must change the order of the lines; secondly, observe whether the cooling tower water distributor is installed The water is uniform and there is no blockage. Finally, observe whether the liquid level control valve of the cooling tower can work normally when the water level rises or falls, that is, whether water is supplied to the tower when the water level drops, and whether the control valve can be closed in time when the water level rises to the upper limit.

　　3. Debugging of terminal equipment

　　3.1 Commissioning of fan coil

　　The fan coil is the main terminal equipment of the central air conditioner. When debugging, first check whether the model of the fan coil is correct. Then turn on the speed control switch of the fan coil, adjust from small to large, and measure the wind speed at the air outlet of the fan coil. If the wind speed does not change, check whether there is a problem with the wiring of the speed control switch.

　　 If the wind speed is not small to large. But from large to small, the wiring sequence of the speed control switch is reversed. After the wind speed is normal, check whether the wind direction is conducive to the return air. The angle of the wind direction can be completed by adjusting the air outlet blades of the fan coil. After turning on the fan coil for a period of time, observe whether the condensate water flows out of the water receiving pan of the coil and into the condensate of the system. If the condensate overflows from the fan coil, it means that the condensate slope of the air conditioning system is not enough, and it should be corrected in time .

　　3.2 Commissioning of the fresh air unit

　　 The fresh air unit needs to be intensively debugged. Since the fresh air unit is cold treated to turn outdoor air into fresh air whose temperature and humidity are suitable for the office environment, the speed and air volume of the fan are the key to the debugging of the fresh air unit. In addition to the fresh air unit, check the air duct system. Since the air supply pipe of the fresh air is easy to be contaminated during installation, the air must be purged after installation. After purging, it is necessary to test whether the ventilation valve and other devices in the air duct work, and whether the air pressure at the new air outlet meets the design requirements