Thermo Scientific VH-D20 Operating Manual page 138

7 • Maintenance and Service
Page 138
6. With the new gas filter assembly, mind the correct orientation for
the gas flow for installation. Observe the flow direction signs on the
filters.
The bottom gas filter must be the charcoal gas filter (thick black
¨
inner filter cylinder; no. 2 in the image below).
The top gas filter must be the HEPA gas filter (thin white inner
¨
filter cylinder; no. 1 in the image below).
7. Push the new gas filter assembly into the clamps observing the
orientation signs for the gas flow on the gas filters. See image below.
Figure 34: Correct orientation of the gas filter assembly
No. Description
1 HEPA gas filter
2 Charcoal gas filter
8. Push the (push-in) elbow fittings into the gas connectors on the
detector. Check that the connections are secure: Slightly pull on the
fittings. If a fitting slides out, repeat this step.
9. Install the protective cover: Hold the protective cover onto the
interior panel. Slide it downward carefully so that the bottom screws
match the recesses.
10. With the screwdriver, tighten the three screws on the protective
cover.
11. Turn on the detector with its main power switch.
12. In Chromeleon, consider updating the Predictive Performance
information for the gas filter assembly.
13. Turn on the gas flow. See
(} page 102).
Turning On/Off the Detector Gas Flow
Charged Aerosol Detectors (VH-D20, VF-D20)
Operating Manual