Hach Ultra MET ONE HHPC-2, User Manual, Page: 14 / 42

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Installation
3.3.3 Install the zero count filter
In a clean-room application, the zero count filter (refer to Figure 3 on page 11 , item 2)
verifies if the MET ONE HHPC–2 is not counting electrical noise signals from internal
components and is not subject to external interference. In indoor air quality and other
applications, the zero count filter cleans out the sensor immediately after a high
concentration sampling.
To connect the zero count filter:
1. Remove the isokinetic probe from the MET ONE HHPC–2.
2. Attach the intake hose barb (MP000026–01).
3. Secure the high purity tubing (VP792002) to the hose barb.
4. Secure the opposite end of the tubing to the zero count filter (VP212808).
Note: Make sure that the arrow of airflow direction or the indicator on the zero count filter points
towards the tubing.
Figure 4 Isokinetic probe with tubing and zero count filter
1 Hose barb fitting 3 Tubing
2 Isokinetic probe 4
MET ONE HHPC–2