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4. Remove the 4 black knobs or turn the 6 polypropylene clips that hold the prefilter grid in place.
This will expose the clogged pre-filter. Do not remove the pre-filter from the hood!
5. Remove the pre-filter from the pre-filter grid and place it inside the poly bag. Wipe any residue off
of the pre-filter grid and base of the enclosure. Place the rag inside the bag with the pre-filter and
seal the bag. Dispose of the pre-filter in accordance with your local guidelines for the substances
that have been used inside the hood.
6. Inspect the HEPA filter for blockage. If replacement is needed, refer to the “FILTER
REPLACEMENT” Type B, sub-section of this manual for complete instructions.
7. Place the new pre-filter into the pre-filter grid and secure into place with the 4 black knobs or 6
polypropylene clips.
8. Dispose of your PPE in accordance with your local guidelines for the substances that have been
used inside the hood.
Figure 8. AC740C Pre-filter clips.
Figure 9. AC740C Pre-filter and HEPA filter.
