Panametrics Aurora H2O, User Manual

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Chapter 7. Troubleshooting
4 Aurora H2O User’s Manual
7.6.2 Using a Moisture Standard
The best moisture standard to use is one generated by a moisture generator as a flowing reference, due to the fact
that static moisture standards in cylinders have limited capability and reliability. A moisture generator such as BH's
MG101 moisture generator (see Figure 105 below) can be used for this purpose.
Figure 105: MG101 Moisture Generator
However, a moisture generator is typically used only in an indoor location with reasonably good temperature control.
In the field this is not always practical, so a more convenient option would be to use a static moisture standard in a
gas cylinder. Consult with your local specialty gas supplier about standards for moisture. Based on application
experience, BH recommends the following guidelines regarding moisture standards in gas cylinders:
• Use passivated, aluminum gas cylinders only.
• Do not use the cylinder when the pressure falls below 50% of the original pressure supplied by the vendor
(typically 1500-1800psig).
• Use the gas cylinder for moisture values of 50–100 ppm.
• Use a moisture standard having a background gas of nitrogen (N2).
• Mix the moisture standard for 10 minutes prior to use, following the manufacturer's guidelines (rolling the
cylinder is typical).
• Use the gas cylinder at the nominal temperature at which the cylinder was tested by the manufacturer.
Whether using a moisture generator or a standard moisture gas cylinder, the source gas should be connected to the
Aurora H2O using the PURGE INLET on the analyzer. Ensure that the sample gas pressure is regulated to a just barely
positive pressure and establish gas flow from the PURGE INLET to the Aurora H2O measurement cell.
7.7 Background Selection Lockout
To prevent accidental selection or tampering, the Background menu option can be disabled using a mechanical
switch located behind the Aurora H2O display. Access to the switch requires removal of the cover, and should be
performed only in non-hazardous conditions.
Note: Unless otherwise requested, the Aurora H2O is shipped with the Background selection
unlocked
.