Despatch LCC/LCD2-14-3 Non Pass Through Series - Manual (Page 20)

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Check that the gaskets are cemented firmly to the filter frame and that
the gasket pieces are butted or mated at the joints.
3.
Pull the shelf out from the oven and set it aside.
4. Loosen the screws at the sides and top of the supply duct/shelf supports on the
right side of the chamber. Pull out the duct/shelf support and set it aside.
5.
Remove the brass nuts and washers from the rods that are holding the filter
frame in place. These nuts will be reused to hold the filter in place.
6.
Remove and discard the conduit spacers from the rods behind the filter frame.
Place the filter in the oven with the seal side towards the right side oven wall.
(LCD ovens using Termikfil filter: place the filter in the oven with the glass braid
seal, not the rolled paper seal, toward the right side oven wall.)
Reinstall the filter frame using the nuts removed earlier. Make sure the filter face
is tight against the inside perimeter of the frame on all sides.
7.
Reinstall the brass nuts and washers to tighten the filter frame down. Tighten the
four nuts alternately for even tightness. Be careful not to over tighten. Correct
installation torque is 28 +/- 3 in-lbs (3.16 +/- .33 N-m). Be sure to compress the
gasket evenly and equally at all points with the filter frame completely covering
the opening.
8.
Reinstall the shelf support/duct assembly using the screws removed earlier.
9.
Reinstall the oven shelf.
HEPA Filter Burn-off
The burn-off process will take place in any piece of equipment where a new HEPA filter
is used at temperatures above 180°C / 356°F. There will be smoke, possibly a pungent
odor, and a light residue on interior surfaces. This is the result of oxidation of the
binder. Most of the binder will leave the filter after running at a temperature of
260°C/500°F for 48 (forty-eight) hours. Check the oven for particles or the exhaust for
smoke and odor to determine that the process is finished.
Select a location for this process where the smoke and odor generated will be ventilated
with the least amount of interruption and inconvenience. Ideally this will be in the final
location for the oven. However, it may be a receiving dock, some well ventilated space
or even outside if the weather is acceptable. If this location is a very clean area, then
special attention must be given to an exhaust hook-up that will capture the smoke and
odor. The post-cleaning (i.e. oven wipe down) may also generate dust, and care should
be taken if this is done in a clean room.
WARNING: Make certain that power is disconnected from
the oven before removing or replacing the HEPA filter.
NOTE: If it is necessary to move the equipment after the burn-off process, considerable
care should be used. The binder which gives strength to new filters is now burned-off and
the media is very fragile. Rough handling of either the filter alone or the equipment with the
filter installed is not recommended as it may tear the media and lead to reduced filter
efficiency. Removal of the filter after heating can also result in damage to the frame seal,
and is only recommended when replacing the filter.