Teledyne 402REU - Hydrocarbon analyzer - Manual (Page 34)

Chapter 4 Model 402 R-EU
Teledyne Analytical Instruments 4-10
such is the case, have the compositions of these gases laboratory-analyzed
before relying on the information obtained from the analyzer.
4.10.2 Supporting Gases
The supporting gases (particularly the fuel and air) should be procured
well in advance of their need. TET/AI suggests that the gases be replaced
when their pressure gauges indicate that the supply is down to 100 psi.
Most cylinder regulators operate marginally in very low pressure ranges.
IMPORTANT: Whenever the fuel or air supply is replaced, the analyzer
must be restandardized. Any hydrocarbons present in these
gases will alter the instrument’s calibration and must be
compensated for through restandardization (see Section 4-
8: Stabilization Period.)