1. The internal surface and built-in components of air-cooled direct expansion air-conditioning unit shall be made of anti-corrosion materials or surface layer, and the material surface shall be smooth and clean.
2. The internal structure should be easy to clean and can smoothly remove the cleaning wastewater, and is not easy to accumulate dust and breed bacteria.
3. The condensate outlet of the surface cooler shall be equipped with a device that can automatically prevent reverse suction and discharge condensate smoothly under negative pressure. In the dehumidification condition, the water should be discharged within 3min of the system operation. The condensate pipe cannot be directly connected with the sewer.
4. Differential pressure gauge shall be set before and after air filters at all levels, and the measuring connecting pipe shall be smooth and tightly installed.
5. Shower type air handling units shall not be used. When the surface cooler is used, the air velocity through the section where the coil is located should not be greater than 2m / s.
6. The humidifier in the air conditioning unit should be dry steam humidifier, and there should be no water drop in the humidification process. The quality of humidified water should meet the sanitary standard of drinking water. The humidifier material shall be corrosion resistant and easy to clean and inspect.
7. There should be enough distance between humidification equipment and its air conditioning equipment section. The relative humidity of air in the air conditioning system before the high-efficiency filter in class I ~ III clean rooms should not be greater than 75%.
8. The sealing of air conditioning unit box should be reliable. When the static pressure value of 1000Pa is maintained in the unit, the air leakage rate of the box shall not be greater than 1% for the system with cleanliness equal to or higher than 1000 grade, and the air leakage rate of the box body shall not be greater than 2% for the system with cleanliness lower than 1000 PA.