Troubleshooting Low Chromatograph Pressure on the Bloodhound

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Troubleshooting Low Chromatograph Pressure on the Bloodhound


Below 1000:  Chromatagraph pressure is essential for the chromatagraph to function properly.
The normal spec is "over 1000"; however, this will drop with altitude.  For example, at 5000
feet in altitude, it may read around 800 - this is fine, so keep in mind your altitude and whether
the readings you are getting from the chromatagraph look realistic before assuming anything
less than 1000 is not enough.

500 to 1000:  While this is indeed low, it may be enough to complete the well, in this case,
you might have to shut off the alarm (register 54 - set to 0 to turn it off), and continue until
the unit can come back to the bench, or a new pump can be provided to the field.  When
repaired, remember to turn this alarm back on.  Field service options in the HOW TO section
below are recommended.

Below 500:  This machine needs either field service operations below are required, or general
service is needed.  Contact Bloodhound Support if the latter.

  There are two known failure modes for the Bloodhound's Chromat Pressure - it will
           either be:

           a)  Drifting below the pressure point, which indicates either an altitude or barometric
                pressure impact to the Chromatograph pressure, or

           b)  It will crash to some very low number (0 to 50) and return sharply to a pressure
                that would normally be ok.  This particular case indicates a pump beginning to fail
                and it warrants replacement of the Chromatograph pump (see image below).

When you receive the "Low Chromotagraph Pressure" Alarm, try these steps: 

1)  Analyze the failure mode using Gas Chart:

     a)  Open the "Gas Chart Control Box" by right-clicking on the black background image 
          anywhere in Gas Chart: 

     b)  Click on the "Setup" button, and choose the "Charting Options" tab.

     c)  Make sure that you have "Chromatograph Pressure" checked (you may want to uncheck
          some other items in order to isolate the Chromatograph Pressure line).

     d)  Zoom out (on the "Gas Chart Control Box") until you can see a trend in the Chromatograph
          pressure line.  Look for these two situations:

          i)  If it's steady but close or dipping below your threshold, you might want to try resetting
               the threshold of the Bloodhound to some lower number (REGISTER 54 - default is 70.
               You might want to try 60 or so to start).

          ii)  If it is "crashing" to a low number, and back to normal again, then the Chromatograph
              pump requires replacement.

1)  Try resetting the Bloodhound.  If you have had a recent rapid change in barometric pressure
      the Bloodhound will re-calibrate on start-up and if this is the issue, it will self-correct.  To reset
      or restart the Bloodhound follow these steps: 

     a)  Remove the power cord from the Bloodhound (see figure below): 

     b)  The Bloodhound will stay on, but will be on battery power.

     c)  To complete the power down, press the "START/STOP" Key on the face
          of the Bloodhound (see figure below):
     d)  To re-power the Bloodhound, plug the power cord back into the power inlet on
          the Bloodhound - it will automatically power on and start up.

2)  If your Bloodhound is experiencing a dipping of pressure

3)  Open the face of the Bloodhound by removing the 4 screws near the handles (see 
     figure below) and try examing the lines feeding the chromatagraph, and check for 
     any loose connections, loose screws, broken or split lines or air filter.  Any of these 
     can cause this alarm. 

3)  Try replacing the chromatagraph pump, in case the pump has gone bad.

4)  As an acid test, if this still persists and you've gone through all available pumps, you 
     can try switching the pump for the normal vacuum pump (which you know to be 
     working).  If the problem persists after this, it is most likely leak in the lines or 
     connections - reinspect these in this case.

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Last Modified:12/7/2013 8:59:08 AM

Last Modified By: syonker

Type: FIX

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