Teledyne 300 Instruction Manual page 27

1.8.3 Internal zero/span
The IZS option includes the valves and connection parts described above, and in addition,
includes an internal zero air scrubber. This scrubber operates by catalyticly converting
CO in the gas stream to CO . If the Analyzer is equipped with the IZS option, Span gas
2
connections should be made as described above and a source of clean air at ambient
pressure should be connected to the IZS/Zero Air Port on the Analyzer's rear panel.
P/N 02163G Teledyne API Model 300 CO Analyzer Instruction Manual - Page 21