The temperature is gradually dropping, and the temperature is cooling across the country. When the winter temperature in the main engine room is lower than 0 ℃, antifreeze measures should be taken for the main engine, refrigerant water pump and cooling water pump, mainly in the following aspects.

1. Host antifreeze

Close the inlet and outlet valves of the host condenser and evaporator, open the drain valve and vent valve, and drain the remaining water.

2. Water pump antifreeze

Close the inlet and outlet valves of the water pump, open the drain valve and vent valve of the water pump, and drain the clean water. Open the valve at the lowest point of the cooling water system, drain the cooling water, and open the drain valve of the water pump. After the system water is drained, in order to prevent rainwater from entering the cooling tower, close the main water outlet valve of the cooling tower, and open the drain valve of the cooling tower water collecting pan , so that the rainwater is drained from the drain valve in time.

3. Antifreeze of cooling tower make-up water pipe

In general, the water supply pipe of the cooling tower is exposed to the outside, and most designers use heat preservation to prevent freezing. However, in actual use, even with heat preservation, frost damage often occurs. In order to solve this problem, when the water supply pipe of the cooling tower is connected from the room, a valve is added, and a water discharge valve is added at the lowest point of the water supply pipe. When winter comes, close the indoor valve, open the lowest point water release valve, and drain the water in the outdoor pipe, so that the pipe does not need to be kept warm and will not be cracked by freezing.

4. Antifreeze of pipelines

The main purpose of chilled water pipe insulation is to prevent condensation on the outside of the pipe, and another function is to prevent the water in the pipe from freezing. The thickness of the insulation layer is generally more than 20mm. In addition, an electric heating cable should be wound on the outside of the water pipe. As long as the heating cable is powered, it can continue to heat the pipe. The temperature of the water in the pipeline is above 10°C. Freezing leads to water shortage protection of the hot water machine. The heating cable should be selected with a temperature limiter, just keep a certain temperature.

5. Antifreeze of surface cooler

When the fresh air unit heats the cold outdoor air in winter, the surface cooler of the fresh air unit is directly in contact with the cold outside air. In order to avoid the surface cooler being damaged by freezing when the heating is stopped, an electric multi-leaf regulating valve can be added at the fresh air inlet, and it can be connected with the Fresh air unit linkage. When the fresh air unit is running, open the air valve, and when the fresh air unit is off, close the air valve, which can effectively prevent the outdoor cold air from directly cooling the water in the surface cooler after the fresh air unit and the refrigerant water pump stop running, causing the water to freeze and freeze. Bad cooler.

6. Antifreeze of the expansion tank

The expansion tank is mainly installed on the roof or in the equipment room on the top floor. Although there are insulation and circulation pipes on the outside, the water in the expansion tank will be frozen in winter because it is kept in a low temperature environment for a long time. Although it is kept warm, it will still be frozen. If the expansion tank is frozen There is no expansion effect, causing the temperature in the system to rise and the pressure to increase.

Therefore, we can set up a DN20 interface in the main water supply pipe of the air conditioner during construction, and install a valve to open properly to ensure that the water in the water tank can be circulated. When the air conditioner is not used at night, the valve can be fully opened before the water pump stops to increase the water temperature in the expansion tank, so that the expansion tank will not freeze for a long time after the pump is stopped.

7. Add antifreeze

In winter, when it is inconvenient for the unit to discharge water and drain the water and the power may be cut off, antifreeze must be added for heating of the equipment, and the minimum local temperature must be used as an important parameter for selecting antifreeze.

The main component of the antifreeze is ethylene glycol. The antifreeze is poured in from the replenishing water tank. After the frozen water in the water system is discharged, the antifreeze stock solution is injected first, and the frozen water is injected if it is not enough, and then the water pump is turned on to make the antifreeze and water fully Fusion, by the way, all the air in the water system should be discharged. The water system should not have air. The presence of air will cause the air conditioner to report to the water flow switch for protection, and it is easy to form cavitation.