"Cooling Fan Manufacturer" reminds 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 with the hot air, chilled water air temperature drop affected; "Cooling Fan Manufacturer" to remind the other hand also affected somewhat cool after the heat exchange of cold air sent, resulting in open air and the room is still not cold phenomenon. Because central air conditioner refrigerant after the 7-degree water into fan coil units, fan coil after becoming exchanged within 15--16 degree cold, so the room temperature is lowered. "Cooling Fan Manufacturer" to remind the importance seen from the above, the presence of fan coil