2H & 2HN Quick Reference Guide


To enter setup, press <↑> then < ENTER >

Press <↑> or <↓> then < ENTER > to select function, then <↑> or <↓> to change

L0 Run

L1 Audible Alarm (On/Off)

L2 0 Sample Time (5 to 120 seconds)

L3 100% Sample Time (5 to 120 seconds)

L4 Decimal Places (3 or 4)

L5 Internal Reference (Current Selection Displayed)

L6 Hour Meter

L7 Factory Defaults

L8 Software Revision

L9 Bar graph (On/Off)

L10 Display Intensity

L11 Optic Option (Check at Start=0, or every Zero=1)

L12 Zero Purge Time (0 to 120 seconds)

L13 100% Purge Time (0 to 120 seconds)


  • < ALARM > Displays Status (On or Off ), <↑> or < > to change, < ENTER > to exit
  • < ALARM > Pressed a second time before < ENTER >, displays Set Point, (0.010 by default) <↑> or <↓> to change
  • < ENTER > Accept Alarm Set Point. Displays On/Off status again, <↑> or <↓>to change.
  • < ENTER > Accept status and return to RUN mode. Alarm LED will remain lit.

*Note: Use L1 to turn the audible portion of the alarm On or Off.


  • Set Selector Valve to CLEAR
  • < REF > (Blinks)
  • < ENTER > Calibration reagent ( PAO or DOP ), also * USER or * HIGH
  • Use <↑> or <↓> to change
  • < ENTER > Displays ug/l of concentration to be displayed as 100 when sampled. Use <↑> or  <↓> to change
  • < ENTER > (O Blinks)
  • < ENTER > Checks Optics (Settings L11=1) and Sets 0%
  • Ready for Testing

* USER is a stored sampled concentration saved by the user, to be displayed as 100%.

*Note: This value is stored in memory until a new value is sampled and saved by the user.  To set: After completing the setting 100% procedure below, Press the REF button and “USER” will be displayed. Press <ENTER>, 0 will blink; turn the Selector Valve to CLEAR, and press <ENTER>

*HIGH allows sampling of concentrations above 130ug/l, exceeding 200ug/l. This setting should only be used for sampling quickly and sparingly, as such concentrations will adversely affect the cleanliness of the optics


  • Connect Upstream Sample Line & set Selector Valve set to UPSTREAM
  • <100> <100> key LED flashes
  • <ENTER> Bar graph scans .The unit averages 100% for a time defined by the L13 setting. When the <0> LED flashes, turn the Selector Valve to Clear
  • <ENTER> Checks optics (if L11=1) and sets 0%.

*Note: This setting can be saved by pressing REF, <ENTER>, and resetting 0.  See *USER above)

  • Ready for Testing


  • GREEN- Optics clean, Internal Reference within 5% of original value
  • ORANGE- Optics affected, Internal Reference shifted to 5% to 10% of original value
  • RED- Optics compromised, Internal Reference shifted by more than 10%. Do NOT rely on Internal Reference.

*Note: The unit can continue to be operated by using the SETTING 100% procedure above.


  • GREEN- Flow within 5% of 1 CFM
  • ORANGE- Flow within 5% to 10% of 1 CFM
  • RED- Flow is more than 10% above or below 1 CFM


*Note: The flow is factory established through 12 feet of sampling tubing.