17 5.2.3 Exhaust Sample Hose - Bosch BEA 050 Produktbeschreibung

5.. Exhaust Sample Hose
Check for signs of damage. If there are any signs of HC
residue and condensation disconnect the exhaust sam-
ple probe from the hose and blow it out in the opposite
direction to the intake flow using compressed air.
5.. Filter
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Bei Austausch der Filter GF1, GF2 und GF3 nur
Originalfilter mit der Bestellnummer 1 687 432 005
verwenden.
If other filters are used (e.g. commercial fuel filters)
the downstream measuring chambers will be damaged
by corrosion residue (e.g. rust particulates through
metal-filter inserts) and an insufficient degree of filter
efficiency.
!
All warranty and goodwill claims will be rendered null
and void in the event of any malfunctions, which are
caused by using the wrong type of filter.
The measuring gas is cleansed of particulates and aero-
sols by a cascade of filters. Particulates are understood
to refer to solid matter such as dust and soot. Aerosols
are minuscule liquid droplets. They can be deposited in
the gas flow and analysis chambers and form linings. In
order to prevent any damage occurring to the exhaust-gas
analyzer, it is necessary to ensure that the correct type
of filter is used and that it is replaced according to the
schedule.
GF1 Filter
This filter cleans the gas flow of the largest particu-
lates. It has to therefore be replaced most frequently of
all the filters.
The replacement interval, depending upon the fre-
quency with which the exhaust-gas analyzer is used, is
approximately twice a week. Where contamination is
excessive (error message lack of flow) change the filter,
this also applies to HC residue.
Bosch Diagnostics
Maintenance | BEA 050 | 
GF2 Input Filter
The second filter cleans the gas flow of additional parti-
culates and aerosols. The dirtier this filter is the smaller
the width of the pores and thus the better the filter
efficiency. It gets wet quickly because of the water in
the exhaust. This humidity washes the aerosols out of
the gas flow and thus leads to a better filtering of parti-
culates .
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A wet filter is therefore desirable.
The replacement interval, depending upon the fre-
quency with which the exhaust-gas analyzer is used, is
approximately once a month to once a year.
Where contamination is excessive (error message lack of
flow) change the filter, this also applies to HC residue.
GF3 Pump Protection Filter
The GF3 filter is provided to protect the pump.
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If the pump protection filter is replaced by a wrong
filter or if it is replaced too frequently the analyzer
chamber in the exhaust-gas analyzer will be contami-
nated.
Where the filter is correctly used it need only be chan-
ged once a year. A wet filter will also act distinctly better
than a dry filter for GF3.
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Abb . 5: Pump protection filter
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1 689 979 832 2007-05-09