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8. Use a 1/2-inch socket on the right end lift bolt and a 7/16-inch socket on the left
end lift bolt, tighten the 2 plenum lift bolts (turning each bolt clockwise will raise
the plenum) until the plenum raises 1/2-inch (13 mm). See Figure 12-19 for
reference.
9. Remove the 3 supply HEPA filter retainer brackets (see Figure 12-20).
11. Lift up on one corner of the supply HEPA filter to break the seal between the filter
gasket and the filter shelf. Once the filter is free, slide it straight out.