Select "Micro Cooling Fan" coil units, in addition to cooling capacity to meet the calculated cooling load requirements, but also required to meet its match sensible heat and latent heat of the room to meet the requirements of heat and moisture ratio; air volume required to meet the supply air temperature, ventilation organizations such as the number and airflow requirements. As central air-conditioning fan coil terminal equipment, its quality determines the effects of indoor air conditioning. At the same time, "Micro Cooling Fan" cleaning problems also directly affect the central air-conditioning effect. A lot of dust particles in the atmosphere, in the long term pumping action under the return air fan aluminum fins filled with dust and dirt, then hand the impact of the heat exchange chilled water and hot air so that the air temperature drops affected; another On the one hand is also affected by the heat, the cold air has cooled exchange sent, resulting in open air and the room is still not cold phenomenon. Because central air conditioner refrigerant after the 7-degree water into the fan coil, after the "Micro Cooling Fan" coil exchange become 15--16 degree cold, so that the room temperature is reduced.