TSI Instruments DustTrak 8520, Operation And Service Manual, Page: 50 / 89

Chapter 4 40
Cleaning the 10 µm Inlet and Sample Tube
The aerosol inlet needs to be cleaned regularly. The inlet nozzle should be
cleaned based on the schedule in Table 4–1 above or especially when
changing from very high concentrations of aerosols to low concentrations.
The “SERVICE 4” message will be displayed during power-up when nozzle
cleaning is due. The D
UST
T
RAK
monitor pauses when any of the service
messages come on. Press any key to bypass the message and continue. The
“SERVICE 4”
message is a one-time indicator to remind you that inlet port
cleaning is due. This message will automatically reset.
1. Move to a relatively clean environment. (Aerosol concentration less
than 0.1 mg/m
3
.)
2. Turn the D
UST
T
RAK
monitor off.
Figure 4–2: Exploded View of Inlet Assembly
3. Remove the sample inlet nozzle and O-ring. The O-ring will usually
stay inside the nozzle.
4. Use the sample tube removal tool to unscrew the tube from the inside of
the inlet port. The cross-pattern on one end of the tool mates with the
end of the sample tube.
5. Use the hook end of the tool to pull the sample tube out of the inlet port.
6. Clean the sample tube and inlet port. A cotton swab can be used to clean
the inside of the inlet port, cap, O-ring, and ends of the tube. The swabs
can be dampened with water or a light solvent (e.g., isopropanol).
Note: Do not use compressed air to clean the inlet area. Compressed
air forces particulates into the optics chamber and
contaminates the optics.