Terra Universal Product Manual
WhisperFlow® Fan Filter Units
©
Copyright 2021 Terra Universal Inc. All rights reserved
•
Revised April 2021
Terra Universal, Inc. • TerraUniversal.com • 800 S. Raymond Ave. • Fullerton, CA 92831 • TEL: (714) 578-6000 • FAX: (714) 578-6020
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4.2
Top-Side Filter Replacement
Topside replaceable FFUs require the units to be removed from the cleanroom ceiling or hood for filter replacement. This
replacement may require shutting down the cleanroom operation.
1.
Disconnect the fan/filter unit from the PDM.
2.
Attach double stick tape to a polypropylene panel – place on all four sides. The panel protects the HEPA filter from
damage (See Figure 11).
3.
Place the polypropylene panel over the filter screen, making sure that it only adheres to the screen without
overlapping the edges (See Figure 12).
4.
Push one side of the FFU up (See Figure 13), rotate it 90° (See Figures 15 and 16) and lower through the ceiling grid.
5.
Place the unit on a flat work surface and remove the 10 sheet metal screws that hold the HEPA/ULPA filter to the
case (See Figure 17).
6.
Replace with a new HEPA/ULPA filter carefully handling edges only.
7.
Secure filter to the case with the same screws used previously.
8.
Place unit back onto the ceiling grid.
Figure 11: Polypropylene panel with tape
Figure 12: Panel attaching to exposed HEPA filter
Figure 13: Panel fully attached to filter screen without
overlapping edges
Figure 14: FFU pushed up on one side for removal
