(2). Change of filterAn air filter is installed on air inlet of the air compressor (see Fig.1-1 ) to prevent the dust in the air from entering the air compressor and reduces noise. After used for a period of time the filter core in the air filter will get clogged. In a result sucking capacity of the air compressor will be reduced, therefore the filter core must be replaced regularly. The way of replace is as follows; open the lid on the air filter, take out the old filter core, put in a new one, and then close the lid.