Troxler ICO 4740, Manual Of Operation And Instruction, Page: 145 / 171

ICO A-7
CAUTION
Do not loosen the nuts that secure the louvers to the
plenum access panel. Moving the louvers will degrade
the factory calibration of the exhaust system.
4. Use a wet/dry vacuum cleaner to clean the soot from the
plenum box. The vacuum cleaner should be equipped
with a filter that has a rating of 0.6 micron or less.
5. Lift the ceramic filter contained in the plenum box out.
Rinse the filter with warm water if the filters appear to
have an excessive amount of soot. Typically, the filters
are self-cleaning and never have to be removed.
6. Using the small, soft-bristled brush provided with the
oven, gently brush all soot from the turbine blades of the
exhaust fan.
CAUTION
Use care when cleaning the turbine to prevent bending
the blades. If a blade is bent, the turbine will be
unbalanced. This will cause excessive vibration and
shorten the life of the fan on the unit.
7. Use the vacuum cleaner to clean the loosened soot from
the turbine.
DO NOT
insert the vacuum cleaner nozzle
into the exhaust fan intake.
CAUTION
To prevent bending the turbine blades, do not insert
the vacuum cleaner nozzle into the fan intake. If a
blade is bent, the turbine will be unbalanced, which will
cause excessive vibration and shorten the life of the fan
8. Replace the plenum box and filter in the proper location.
Then tighten screws that hold plenum box cover in
place.
9. Replace top cover.