Antifreeze measures for large central air-conditioning systems

Air-conditioning maintenance company tells you the anti-freezing measures and methods of large-scale central air-conditioning systems:

Antifreeze of main engine and water pump

Anti-freezing of the main engine: close the inlet and outlet valves of the condenser and evaporator of the main engine, open the drain valve and the vent valve, and then use compressed air to blow off the remaining water.

Anti-freezing of water pump: put the pump in a normal temperature environment, above zero. If the water pump freezes, use hot water or boiling water into the water pump to melt the ice. Or heating the water pump housing. When the water pump is out of service, close the inlet and outlet valves of the refrigerant water pump, open the drain valve and the vent valve of the water pump, and drain clean water. Open the low point valve of the cooling water system, drain the cooling water, and open the water pump drain valve. After the system water is drained, in order to prevent rainwater from entering through the cooling tower, close the cooling tower water main valve and open the cooling tower water tray drain valve , So that the rainwater can be drained from the drain valve in time. Centrifugal pumps can do some antifreeze maintenance on the pump body and pipelines. The outer surface of the pump can be wrapped with cotton wool or cloth, and the pipe can be wrapped with straw cloth. You can also apply antifreeze paint and other measures.

Antifreeze of cooling tower water supply pipe

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

Antifreeze of fresh air unit

The function of the fresh air unit is to process the outdoor fresh air and send it into each room. In winter, the fresh air unit heats the outdoor cold air, that is, the surface cooler of the fresh air unit directly contacts the outside cold air, in order to prevent the surface cooler from being frozen when the heating is stopped. , An electric multi-blade control valve should be added at the fresh air inlet and linked with the fresh air unit. When the fresh air unit is running, the air valve is opened, and when the fresh fan is closed, the air valve is closed. This can prevent the fresh air unit and the refrigerant water pump from stopping. The outdoor cold air directly cools the water in the surface cooler, which freezes the water and damages the surface cooler.

The Shanghai Central Air-Conditioning Project reminds that before the fresh air unit is turned on in winter, it is necessary to check whether the water in the system is flowing and the temperature is appropriate. If the water pump is not running, the fresh air unit cannot be turned on. If the water pump is running but the water temperature is low, the fresh air unit cannot be turned on.