At the beginning of each heating / cooling season, the system should be checked as follows:
Filters may be duct-mounted or installed in the cabinet. A filter is installed at the factory. Note that filter access door fits over access panel. Air will leak if the access panel is placed over the filter door.
Filters should be inspected monthly and must be cleaned or replaced when dirty to assure proper air handler operation.
Units are equipped with standard throw-away type filters which should be replaced when dirty.
To remove filter, loosen the thumbscrews holding the filter panel in place. Slide filter out of the guides on either side of cabinet, insert new filter and replace panel.
B-Supply Air Blower
Source: MaintainX (Community Member)