Air-Return Pipe - Bosch FAS-420-TT Series Operation Manual

92 en | Installation of the pipe system
1.
2.
Notice!
In applications with largely fine dust build-up, three fine dust filters can also be used (subject
to separate order).
6.6

Air-return Pipe

Fix the air-return pipe within the air exhaust opening. No additional components are required.
Caution!
In the event of sharp temperature fluctuations, the pipe must be fixed immediately in front of
!
the unit so that the pipe does not pull out of the pipe connection due to length change (see
Length Change of the Pipe System, page 86 ).
Steps:
1.
2.
Refer to
–
2020.04 | 6.1 | F.01U.029.275
Remove the four screws and remove the housing cover.
Remove the old filter inserts and clean the inside of the housing carefully to remove dust.
Now fit the cleaned or new filter inserts. When using the spare filter set for the large
filterbox, ensure you follow the correct sequence (see label on base of housing).
Replace the housing cover and screw it back on.
Remove the pre-punched pipe opening in the protective grille of the air exhaust opening
(e.g. using a small edge cutter).
Insert the air-return pipe through the opened pipe opening in the protective grille and fix
it to the FAS-420 with the rubber ring already integrated into the air-exhaust opening.
Length Change of the Pipe System, page 86
1
Operation guide
Aspiration smoke detector LSN improved
1 Air-return pipe (aspiration
pipe)
Bosch Sicherheitssysteme GmbH